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ADMDecomposition.wl
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(* ::Package:: *)
ADMDecomposition[] := {"Minkowski", "Schwarzschild", "Kerr", "ReissnerNordstrom", "KerrNewman", "BrillLindquist", "FLRW"}
ADMDecomposition["Minkowski"] := ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[ConstantArray[1, 3]],
(Superscript["\[FormalX]", ToString[#1]] & ) /@ Range[3], True, True], "\[FormalT]",
"\[FormalAlpha]" @@ Join[{"\[FormalT]"}, (Superscript["\[FormalX]", ToString[#1]] & ) /@ Range[3]],
(Module[{index = #1}, Superscript["\[FormalBeta]", index] @@ Join[{"\[FormalT]"}, (Superscript["\[FormalX]", ToString[#1]] & ) /@
Range[3]]] & ) /@ Range[3]]
ADMDecomposition["Minkowski", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[ConstantArray[1, 3]], coordinates, True, True],
timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition["Minkowski", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[ConstantArray[1, 3]], coordinates, True, True],
timeCoordinate, lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"Minkowski", dimensionCount_Integer}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[ConstantArray[1, dimensionCount - 1]],
(Superscript["\[FormalX]", ToString[#1]] & ) /@ Range[dimensionCount - 1], True, True], "\[FormalT]",
"\[FormalAlpha]" @@ Join[{"\[FormalT]"}, (Superscript["\[FormalX]", ToString[#1]] & ) /@ Range[dimensionCount - 1]],
(Module[{index = #1}, Superscript["\[Beta]", index] @@ Join[{"\[FormalT]"}, (Superscript["\[FormalX]", ToString[#1]] & ) /@
Range[dimensionCount - 1]]] & ) /@ Range[dimensionCount - 1]]
ADMDecomposition[{"Minkowski", dimensionCount_Integer}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[ConstantArray[1, dimensionCount - 1]], coordinates,
True, True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[dimensionCount - 1]] /;
Length[coordinates] == dimensionCount - 1
ADMDecomposition[{"Minkowski", dimensionCount_Integer}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[ConstantArray[1, dimensionCount - 1]], coordinates, True, True], timeCoordinate, lapseFunction,
shiftVector] /; Length[coordinates] == dimensionCount - 1 && Length[shiftVector] == dimensionCount - 1
ADMDecomposition["Schwarzschild"] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{1/(1 - (2*"\[FormalCapitalM]")/"\[FormalR]"), "\[FormalR]"^2, "\[FormalR]"^2*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]",
"\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition["Schwarzschild", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{1/(1 - (2*"\[FormalCapitalM]")/coordinates[[1]]),
coordinates[[1]]^2, coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition["Schwarzschild", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{1/(1 - (2*"\[FormalCapitalM]")/coordinates[[1]]),
coordinates[[1]]^2, coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"Schwarzschild", mass_}] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{1/(1 - (2*mass)/"\[FormalR]"), "\[FormalR]"^2, "\[FormalR]"^2*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]",
"\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"Schwarzschild", mass_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{1/(1 - (2*mass)/coordinates[[1]]),
coordinates[[1]]^2, coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"Schwarzschild", mass_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{1/(1 - (2*mass)/coordinates[[1]]),
coordinates[[1]]^2, coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition["Kerr"] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*"\[FormalCapitalM]"*"\[FormalR]" + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2),
"\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2, ("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + (2*"\[FormalR]"*("\[FormalCapitalJ]"^2/"\[FormalCapitalM]")*Sin["\[FormalTheta]"]^2)/
("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2))*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]",
"\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition["Kerr", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2,
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + (2*coordinates[[1]]*("\[FormalCapitalJ]"^2/"\[FormalCapitalM]")*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True,
True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition["Kerr", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2,
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + (2*coordinates[[1]]*("\[FormalCapitalJ]"^2/"\[FormalCapitalM]")*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True,
True], timeCoordinate, lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"Kerr", mass_}] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*mass*"\[FormalR]" + ("\[FormalCapitalJ]"/mass)^2),
"\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2, ("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2 + (2*"\[FormalR]"*("\[FormalCapitalJ]"^2/mass)*Sin["\[FormalTheta]"]^2)/
("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2))*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]",
"\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"Kerr", mass_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2,
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2 + (2*coordinates[[1]]*("\[FormalCapitalJ]"^2/mass)*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True,
True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"Kerr", mass_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2,
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2 + (2*coordinates[[1]]*("\[FormalCapitalJ]"^2/mass)*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True,
True], timeCoordinate, lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"Kerr", mass_, angularMomentum_}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*mass*"\[FormalR]" + (angularMomentum/mass)^2),
"\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2, ("\[FormalR]"^2 + (angularMomentum/mass)^2 +
(2*"\[FormalR]"*(angularMomentum^2/mass)*Sin["\[FormalTheta]"]^2)/("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2))*
Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"Kerr", mass_, angularMomentum_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2), coordinates[[1]]^2 + (angularMomentum/mass)^2*
Cos[coordinates[[2]]]^2, (coordinates[[1]]^2 + (angularMomentum/mass)^2 +
(2*coordinates[[1]]*(angularMomentum^2/mass)*Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 +
(angularMomentum/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True, True],
timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"Kerr", mass_, angularMomentum_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/
(coordinates[[1]]^2 - 2*mass*coordinates[[1]] + (angularMomentum/mass)^2),
coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2,
(coordinates[[1]]^2 + (angularMomentum/mass)^2 + (2*coordinates[[1]]*(angularMomentum^2/mass)*
Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2))*
Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate, lapseFunction, shiftVector] /;
Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition["ReissnerNordstrom"] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{1/(1 - (2*"\[FormalCapitalM]")/"\[FormalR]" + "\[FormalCapitalQ]"^2/(4*Pi*"\[FormalR]"^2)), "\[FormalR]"^2, "\[FormalR]"^2*Sin["\[FormalTheta]"]^2}],
{"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition["ReissnerNordstrom", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{1/(1 - (2*"\[FormalCapitalM]")/coordinates[[1]] + "\[FormalCapitalQ]"^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition["ReissnerNordstrom", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{1/(1 - (2*"\[FormalCapitalM]")/coordinates[[1]] + "\[FormalCapitalQ]"^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate, lapseFunction,
shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"ReissnerNordstrom", mass_}] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{1/(1 - (2*mass)/"\[FormalR]" + "\[FormalCapitalQ]"^2/(4*Pi*"\[FormalR]"^2)), "\[FormalR]"^2, "\[FormalR]"^2*Sin["\[FormalTheta]"]^2}],
{"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"ReissnerNordstrom", mass_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{1/(1 - (2*mass)/coordinates[[1]] + "\[FormalCapitalQ]"^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"ReissnerNordstrom", mass_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{1/(1 - (2*mass)/coordinates[[1]] + "\[FormalCapitalQ]"^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate, lapseFunction,
shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"ReissnerNordstrom", mass_, charge_}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{1/(1 - (2*mass)/"\[FormalR]" + charge^2/(4*Pi*"\[FormalR]"^2)),
"\[FormalR]"^2, "\[FormalR]"^2*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"ReissnerNordstrom", mass_, charge_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{1/(1 - (2*mass)/coordinates[[1]] + charge^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"ReissnerNordstrom", mass_, charge_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{1/(1 - (2*mass)/coordinates[[1]] + charge^2/(4*Pi*coordinates[[1]]^2)), coordinates[[1]]^2,
coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate, lapseFunction,
shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition["KerrNewman"] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*"\[FormalCapitalM]"*"\[FormalR]" + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 +
"\[FormalCapitalQ]"^2/(4*Pi)), "\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2,
((("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2)^2 - ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*("\[FormalR]"^2 - 2*"\[FormalCapitalM]"*"\[FormalR]" + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + "\[FormalCapitalQ]"^2/(4*Pi))*
Sin["\[FormalTheta]"]^2)/("\[FormalR]"^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos["\[FormalTheta]"]^2))*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True],
"\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition["KerrNewman", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + "\[FormalCapitalQ]"^2/(4*Pi)), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2)^2 - ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition["KerrNewman", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + "\[FormalCapitalQ]"^2/(4*Pi)), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2)^2 - ("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*(coordinates[[1]]^2 - 2*"\[FormalCapitalM]"*coordinates[[1]] +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 +
("\[FormalCapitalJ]"/"\[FormalCapitalM]")^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"KerrNewman", mass_}] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*mass*"\[FormalR]" + ("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi)),
"\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2,
((("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2)^2 - ("\[FormalCapitalJ]"/mass)^2*("\[FormalR]"^2 - 2*mass*"\[FormalR]" + ("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*
Sin["\[FormalTheta]"]^2)/("\[FormalR]"^2 + ("\[FormalCapitalJ]"/mass)^2*Cos["\[FormalTheta]"]^2))*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True],
"\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"KerrNewman", mass_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi)), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2)^2 - ("\[FormalCapitalJ]"/mass)^2*(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 +
("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"KerrNewman", mass_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi)), coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2)^2 - ("\[FormalCapitalJ]"/mass)^2*(coordinates[[1]]^2 - 2*mass*coordinates[[1]] +
("\[FormalCapitalJ]"/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/(coordinates[[1]]^2 +
("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*mass*"\[FormalR]" + (angularMomentum/mass)^2 +
"\[FormalCapitalQ]"^2/(4*Pi)), "\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2,
((("\[FormalR]"^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*("\[FormalR]"^2 - 2*mass*"\[FormalR]" +
(angularMomentum/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin["\[FormalTheta]"]^2)/("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2))*
Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi)),
coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates,
True, True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/
(coordinates[[1]]^2 - 2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi)),
coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + "\[FormalCapitalQ]"^2/(4*Pi))*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + ("\[FormalCapitalJ]"/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates, True,
True], timeCoordinate, lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_, charge_}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2)/("\[FormalR]"^2 - 2*mass*"\[FormalR]" + (angularMomentum/mass)^2 +
charge^2/(4*Pi)), "\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2,
((("\[FormalR]"^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*("\[FormalR]"^2 - 2*mass*"\[FormalR]" +
(angularMomentum/mass)^2 + charge^2/(4*Pi))*Sin["\[FormalTheta]"]^2)/("\[FormalR]"^2 + (angularMomentum/mass)^2*Cos["\[FormalTheta]"]^2))*
Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_, charge_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + charge^2/(4*Pi)),
coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + charge^2/(4*Pi))*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates,
True, True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"KerrNewman", mass_, angularMomentum_, charge_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2)/
(coordinates[[1]]^2 - 2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + charge^2/(4*Pi)),
coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2,
(((coordinates[[1]]^2 + (angularMomentum/mass)^2)^2 - (angularMomentum/mass)^2*(coordinates[[1]]^2 -
2*mass*coordinates[[1]] + (angularMomentum/mass)^2 + charge^2/(4*Pi))*Sin[coordinates[[2]]]^2)/
(coordinates[[1]]^2 + (angularMomentum/mass)^2*Cos[coordinates[[2]]]^2))*Sin[coordinates[[2]]]^2}], coordinates,
True, True], timeCoordinate, lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition["BrillLindquist"] := Module[{brillLindquistPotential},
brillLindquistPotential = 1 + (1/2)*("\[FormalCapitalM]"/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] - Subscript["\[FormalZ]", "0"])^2] +
"\[FormalCapitalM]"/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
"\[FormalR]"^2*brillLindquistPotential^4, ("\[FormalR]"^2*Sin["\[FormalTheta]"]^2)*brillLindquistPotential^4}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]]
ADMDecomposition["BrillLindquist", timeCoordinate_, coordinates_List] :=
Module[{brillLindquistPotential}, brillLindquistPotential =
1 + (1/2)*("\[FormalCapitalM]"/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] -
Subscript["\[FormalZ]", "0"])^2] + "\[FormalCapitalM]"/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]]] /; Length[coordinates] == 3
ADMDecomposition["BrillLindquist", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
Module[{brillLindquistPotential}, brillLindquistPotential =
1 + (1/2)*("\[FormalCapitalM]"/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] -
Subscript["\[FormalZ]", "0"])^2] + "\[FormalCapitalM]"/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate, lapseFunction, shiftVector]] /;
Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"BrillLindquist", mass_}] := Module[{brillLindquistPotential},
brillLindquistPotential = 1 + (1/2)*(mass/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] - Subscript["\[FormalZ]", "0"])^2] +
mass/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
"\[FormalR]"^2*brillLindquistPotential^4, ("\[FormalR]"^2*Sin["\[FormalTheta]"]^2)*brillLindquistPotential^4}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]]
ADMDecomposition[{"BrillLindquist", mass_}, timeCoordinate_, coordinates_List] :=
Module[{brillLindquistPotential}, brillLindquistPotential =
1 + (1/2)*(mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] -
Subscript["\[FormalZ]", "0"])^2] + mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]]] /; Length[coordinates] == 3
ADMDecomposition[{"BrillLindquist", mass_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
Module[{brillLindquistPotential}, brillLindquistPotential =
1 + (1/2)*(mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] -
Subscript["\[FormalZ]", "0"])^2] + mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] + Subscript["\[FormalZ]", "0"])^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate, lapseFunction, shiftVector]] /;
Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"BrillLindquist", mass_, position_}] := Module[{brillLindquistPotential},
brillLindquistPotential = 1 + (1/2)*(mass/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] - position)^2] +
mass/Sqrt["\[FormalR]"^2*Sin["\[FormalTheta]"]^2 + ("\[FormalR]"*Cos["\[FormalTheta]"] + position)^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
"\[FormalR]"^2*brillLindquistPotential^4, ("\[FormalR]"^2*Sin["\[FormalTheta]"]^2)*brillLindquistPotential^4}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]]
ADMDecomposition[{"BrillLindquist", mass_, position_}, timeCoordinate_, coordinates_List] :=
Module[{brillLindquistPotential}, brillLindquistPotential =
1 + (1/2)*(mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] -
position)^2] + mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] + position)^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]]] /; Length[coordinates] == 3
ADMDecomposition[{"BrillLindquist", mass_, position_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := Module[{brillLindquistPotential},
brillLindquistPotential = 1 + (1/2)*(mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 +
(coordinates[[1]]*Cos[coordinates[[2]]] - position)^2] +
mass/Sqrt[coordinates[[1]]^2*Sin[coordinates[[2]]]^2 + (coordinates[[1]]*Cos[coordinates[[2]]] + position)^2]);
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{brillLindquistPotential^4,
coordinates[[1]]^2*brillLindquistPotential^4, (coordinates[[1]]^2*Sin[coordinates[[2]]]^2)*
brillLindquistPotential^4}], coordinates, True, True], timeCoordinate, lapseFunction, shiftVector]] /;
Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition["FLRW"] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{"\[FormalA]"["\[FormalT]"]^2/(1 - "\[FormalK]"*"\[FormalR]"^2), "\[FormalA]"["\[FormalT]"]^2*"\[FormalR]"^2, "\[FormalA]"["\[FormalT]"]^2*"\[FormalR]"^2*Sin["\[FormalTheta]"]^2}],
{"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"},
(Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition["FLRW", timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{"\[FormalA]"[timeCoordinate]^2/(1 - "\[FormalK]"*coordinates[[1]]^2), "\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2,
"\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[FormalA]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition["FLRW", timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{"\[FormalA]"[timeCoordinate]^2/(1 - "\[FormalK]"*coordinates[[1]]^2), "\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2,
"\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"FLRW", curvature_}] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{"\[FormalA]"["\[FormalT]"]^2/(1 - curvature*"\[FormalR]"^2), "\[FormalA]"["\[FormalT]"]^2*"\[FormalR]"^2,
"\[FormalA]"["\[FormalT]"]^2*"\[FormalR]"^2*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True], "\[FormalT]",
"\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"FLRW", curvature_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{"\[FormalA]"[timeCoordinate]^2/(1 - curvature*coordinates[[1]]^2), "\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2,
"\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
"\[Alpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"FLRW", curvature_}, timeCoordinate_, coordinates_List, lapseFunction_, shiftVector_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{"\[FormalA]"[timeCoordinate]^2/(1 - curvature*coordinates[[1]]^2), "\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2,
"\[FormalA]"[timeCoordinate]^2*coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate,
lapseFunction, shiftVector] /; Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[{"FLRW", curvature_, scaleFactor_}] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[{scaleFactor["\[FormalT]"]^2/(1 - curvature*"\[FormalR]"^2),
scaleFactor["\[FormalT]"]^2*"\[FormalR]"^2, scaleFactor["\[FormalT]"]^2*"\[FormalR]"^2*Sin["\[FormalTheta]"]^2}], {"\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, True, True],
"\[FormalT]", "\[FormalAlpha]" @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"}, (Superscript["\[FormalBeta]", #1] @@ {"\[FormalT]", "\[FormalR]", "\[FormalTheta]", "\[FormalPhi]"} & ) /@ Range[3]]
ADMDecomposition[{"FLRW", curvature_, scaleFactor_}, timeCoordinate_, coordinates_List] :=
ADMDecomposition[ResourceFunction["MetricTensor"][DiagonalMatrix[
{scaleFactor[timeCoordinate]^2/(1 - curvature*coordinates[[1]]^2), scaleFactor[timeCoordinate]^2*
coordinates[[1]]^2, scaleFactor[timeCoordinate]^2*coordinates[[1]]^2*Sin[coordinates[[2]]]^2}], coordinates,
True, True], timeCoordinate, "\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates],
(Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@ Range[3]] /; Length[coordinates] == 3
ADMDecomposition[{"FLRW", curvature_, scaleFactor_}, timeCoordinate_, coordinates_List, lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][
DiagonalMatrix[{scaleFactor[timeCoordinate]^2/(1 - curvature*coordinates[[1]]^2),
scaleFactor[timeCoordinate]^2*coordinates[[1]]^2, scaleFactor[timeCoordinate]^2*coordinates[[1]]^2*
Sin[coordinates[[2]]]^2}], coordinates, True, True], timeCoordinate, lapseFunction, shiftVector] /;
Length[coordinates] == 3 && Length[shiftVector] == 3
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_]] :=
ADMDecomposition[ResourceFunction["MetricTensor"][matrixRepresentation, coordinates, index1, index2], "\[FormalT]",
"\[FormalAlpha]" @@ Join[{"\[FormalT]"}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{"\[FormalT]"}, coordinates] & ) /@
Range[Length[matrixRepresentation]]] /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_] :=
ADMDecomposition[ResourceFunction["MetricTensor"][matrixRepresentation, coordinates, index1, index2], timeCoordinate,
"\[FormalAlpha]" @@ Join[{timeCoordinate}, coordinates], (Superscript["\[FormalBeta]", #1] @@ Join[{timeCoordinate}, coordinates] & ) /@
Range[Length[matrixRepresentation]]] /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], lapseFunction_,
shiftVector_List] := ADMDecomposition[ResourceFunction["MetricTensor"][matrixRepresentation, coordinates, index1,
index2], "\[FormalT]", lapseFunction, shiftVector] /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2] && Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SpatialMetricTensor"] :=
ResourceFunction["MetricTensor"][matrixRepresentation, coordinates, index1, index2] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SpacetimeMetricTensor"] :=
Module[{shiftCovector},
shiftCovector = Normal[SparseArray[(Module[{index = #1}, index -> Total[(matrixRepresentation[[index,#1]]*
shiftVector[[#1]] & ) /@ Range[Length[matrixRepresentation]]]] & ) /@
Range[Length[matrixRepresentation]]]]; ResourceFunction["MetricTensor"][
Normal[SparseArray[Join[{{1, 1} -> Total[(shiftVector[[#1]]*shiftCovector[[#1]] & ) /@
Range[Length[matrixRepresentation]]] - lapseFunction^2},
(Module[{index = #1}, {1, index + 1} -> Total[(matrixRepresentation[[index,#1]]*shiftVector[[#1]] & ) /@ Range[
Length[matrixRepresentation]]]] & ) /@ Range[Length[matrixRepresentation]],
(Module[{index = #1}, {index + 1, 1} -> Total[(matrixRepresentation[[#1,index]]*shiftVector[[#1]] & ) /@ Range[
Length[matrixRepresentation]]]] & ) /@ Range[Length[matrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> matrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[matrixRepresentation]], 2]]]], Join[{timeCoordinate}, coordinates], True, True]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["NormalVector"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spacetimeMetricTensor}, newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]];
Normal[SparseArray[(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,
#1]]*D[newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["ReducedNormalVector"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spacetimeMetricTensor}, newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]];
FullSimplify[
Normal[SparseArray[(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,
#1]]*D[newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@
Range[Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SymbolicNormalVector"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spacetimeMetricTensor}, newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]];
Normal[SparseArray[(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,
#1]]*Inactive[D][newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["TimeVector"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spacetimeMetricTensor, normalVector}, newMatrixRepresentation = matrixRepresentation /.
(#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newCoordinates = coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
D[newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
Normal[SparseArray[(Module[{index = #1}, index -> newLapseFunction*normalVector[[index]] +
Join[{0}, newShiftVector][[index]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SymbolicTimeVector"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spacetimeMetricTensor, normalVector}, newMatrixRepresentation = matrixRepresentation /.
(#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newCoordinates = coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
Inactive[D][newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
Normal[SparseArray[(Module[{index = #1}, index -> newLapseFunction*normalVector[[index]] +
Join[{0}, newShiftVector][[index]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["TimeCoordinate"] :=
timeCoordinate /; SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SpatialCoordinates"] :=
coordinates /; SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["CoordinateOneForms"] :=
(If[Head[#1] === Subscript, Subscript[StringJoin["\[FormalD]", ToString[First[#1]]], ToString[Last[#1]]],
If[Head[#1] === Superscript, Superscript[StringJoin["\[FormalD]", ToString[First[#1]]], ToString[Last[#1]]],
StringJoin["\[FormalD]", ToString[#1]]]] & ) /@ Join[{timeCoordinate}, coordinates] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["LapseFunction"] :=
lapseFunction /; SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["ShiftVector"] := shiftVector /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2] && Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["GaussEquations"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, mixedExtrinsicCurvatureTensor, spatialRiemannTensor,
spacetimeMetricTensor, spacetimeChristoffelSymbols, spacetimeRiemannTensor, normalVector, projectionOperator,
leftHandSide, rightHandSide}, newMatrixRepresentation = matrixRepresentation /.
(#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newCoordinates = coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spatialChristoffelSymbols = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((1/2)*Inverse[newMatrixRepresentation][[index[[1]],#1]]*
(D[newMatrixRepresentation[[#1,index[[3]]]], newCoordinates[[index[[2]]]]] + D[newMatrixRepresentation[[
index[[2]],#1]], newCoordinates[[index[[3]]]]] - D[newMatrixRepresentation[[index[[2]],index[[3]]]],
newCoordinates[[#1]]]) & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 3]]]; extrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> (1/(2*newLapseFunction))*(D[shiftCovector[[First[index]]],
newCoordinates[[Last[index]]]] - Total[(spatialChristoffelSymbols[[#1,Last[index],First[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] + D[shiftCovector[[Last[index]]],
newCoordinates[[First[index]]]] - Total[(spatialChristoffelSymbols[[#1,First[index],Last[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] - D[newMatrixRepresentation[[
First[index],Last[index]]], newTimeCoordinate])] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
2]]]; mixedExtrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(Inverse[newMatrixRepresentation][[First[index],#1]]*
extrinsicCurvatureTensor[[#1,Last[index]]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; spatialRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> D[spatialChristoffelSymbols[[index[[1]],index[[2]],index[[4]]]],
newCoordinates[[index[[3]]]]] - D[spatialChristoffelSymbols[[index[[1]],index[[2]],index[[3]]]],
newCoordinates[[index[[4]]]]] + Total[(spatialChristoffelSymbols[[index[[1]],#1,index[[3]]]]*
spatialChristoffelSymbols[[#1,index[[2]],index[[4]]]] & ) /@ Range[Length[newMatrixRepresentation]]] -
Total[(spatialChristoffelSymbols[[index[[1]],#1,index[[4]]]]*spatialChristoffelSymbols[[#1,index[[2]],
index[[3]]]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 4]]]; spacetimeMetricTensor =
Normal[SparseArray[Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]] - newLapseFunction^2},
(Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
(Module[{index = #1}, {index + 1, 1} -> Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]]; spacetimeChristoffelSymbols =
Normal[SparseArray[(Module[{index = #1}, index -> Total[((1/2)*Inverse[spacetimeMetricTensor][[index[[1]],#1]]*
(D[spacetimeMetricTensor[[#1,index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[2]]]]] +
D[spacetimeMetricTensor[[index[[2]],#1]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] -
D[spacetimeMetricTensor[[index[[2]],index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[
#1]]]) & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 3]]]; spacetimeRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> D[spacetimeChristoffelSymbols[[index[[1]],index[[2]],index[[
4]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] - D[spacetimeChristoffelSymbols[[index[[
1]],index[[2]],index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[4]]]]] +
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[3]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[4]]]] & ) /@ Range[Length[spacetimeMetricTensor]]] -
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[4]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[3]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
D[newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
projectionOperator = Normal[SparseArray[(Module[{index = #1}, index -> KroneckerDelta[First[index], Last[index]] +
Total[(normalVector[[Last[index]]]*spacetimeMetricTensor[[First[index],#1]]*normalVector[[#1]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
leftHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(Module[{nestedIndex = #1}, projectionOperator[[nestedIndex[[1]],
index[[1]] + 1]]*projectionOperator[[index[[2]] + 1,nestedIndex[[2]]]]*projectionOperator[[
index[[3]] + 1,nestedIndex[[3]]]]*projectionOperator[[index[[4]] + 1,nestedIndex[[4]]]]*
spacetimeRiemannTensor[[nestedIndex[[1]],nestedIndex[[2]],nestedIndex[[3]],nestedIndex[[4]]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
4]]]; rightHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> spatialRiemannTensor[[index[[1]],index[[2]],index[[3]],index[[4]]]] +
mixedExtrinsicCurvatureTensor[[index[[1]],index[[3]]]]*extrinsicCurvatureTensor[[index[[2]],index[[4]]]] -
mixedExtrinsicCurvatureTensor[[index[[1]],index[[4]]]]*extrinsicCurvatureTensor[[index[[2]],index[[
3]]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 4]]];
Thread[Catenate[Catenate[Catenate[leftHandSide]]] == Catenate[Catenate[Catenate[rightHandSide]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SymbolicGaussEquations"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, mixedExtrinsicCurvatureTensor, spatialRiemannTensor,
spacetimeMetricTensor, spacetimeChristoffelSymbols, spacetimeRiemannTensor, normalVector, projectionOperator,
leftHandSide, rightHandSide}, newMatrixRepresentation = matrixRepresentation /.
(#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newCoordinates = coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spatialChristoffelSymbols = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((1/2)*Inverse[newMatrixRepresentation][[index[[1]],#1]]*
(Inactive[D][newMatrixRepresentation[[#1,index[[3]]]], newCoordinates[[index[[2]]]]] +
Inactive[D][newMatrixRepresentation[[index[[2]],#1]], newCoordinates[[index[[3]]]]] -
Inactive[D][newMatrixRepresentation[[index[[2]],index[[3]]]], newCoordinates[[#1]]]) & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 3]]];
extrinsicCurvatureTensor = Normal[SparseArray[
(Module[{index = #1}, index -> (1/(2*newLapseFunction))*(Inactive[D][shiftCovector[[First[index]]],
newCoordinates[[Last[index]]]] - Total[(spatialChristoffelSymbols[[#1,Last[index],First[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] + Inactive[D][shiftCovector[[
Last[index]]], newCoordinates[[First[index]]]] - Total[(spatialChristoffelSymbols[[#1,First[index],
Last[index]]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
Inactive[D][newMatrixRepresentation[[First[index],Last[index]]], newTimeCoordinate])] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; mixedExtrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(Inverse[newMatrixRepresentation][[First[index],#1]]*
extrinsicCurvatureTensor[[#1,Last[index]]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; spatialRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Inactive[D][spatialChristoffelSymbols[[index[[1]],index[[
2]],index[[4]]]], newCoordinates[[index[[3]]]]] - Inactive[D][spatialChristoffelSymbols[[index[[1]],
index[[2]],index[[3]]]], newCoordinates[[index[[4]]]]] + Total[(spatialChristoffelSymbols[[index[[1]],#1,
index[[3]]]]*spatialChristoffelSymbols[[#1,index[[2]],index[[4]]]] & ) /@ Range[
Length[newMatrixRepresentation]]] - Total[(spatialChristoffelSymbols[[index[[1]],#1,index[[4]]]]*
spatialChristoffelSymbols[[#1,index[[2]],index[[3]]]] & ) /@ Range[Length[
newMatrixRepresentation]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 4]]];
spacetimeMetricTensor = Normal[SparseArray[
Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
newLapseFunction^2}, (Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*
newShiftVector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Range[Length[newMatrixRepresentation]], (Module[{index = #1}, {index + 1, 1} ->
Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@ Range[
Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]]; spacetimeChristoffelSymbols =
Normal[SparseArray[(Module[{index = #1}, index -> Total[((1/2)*Inverse[spacetimeMetricTensor][[index[[1]],#1]]*
(Inactive[D][spacetimeMetricTensor[[#1,index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[
index[[2]]]]] + Inactive[D][spacetimeMetricTensor[[index[[2]],#1]], Join[{newTimeCoordinate},
newCoordinates][[index[[3]]]]] - Inactive[D][spacetimeMetricTensor[[index[[2]],index[[3]]]],
Join[{newTimeCoordinate}, newCoordinates][[#1]]]) & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 3]]]; spacetimeRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Inactive[D][spacetimeChristoffelSymbols[[index[[1]],index[[
2]],index[[4]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] -
Inactive[D][spacetimeChristoffelSymbols[[index[[1]],index[[2]],index[[3]]]], Join[{newTimeCoordinate},
newCoordinates][[index[[4]]]]] + Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[3]]]]*
spacetimeChristoffelSymbols[[#1,index[[2]],index[[4]]]] & ) /@ Range[Length[spacetimeMetricTensor]]] -
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[4]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[3]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
Inactive[D][newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
projectionOperator = Normal[SparseArray[(Module[{index = #1}, index -> KroneckerDelta[First[index], Last[index]] +
Total[(normalVector[[Last[index]]]*spacetimeMetricTensor[[First[index],#1]]*normalVector[[#1]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
leftHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(Module[{nestedIndex = #1}, projectionOperator[[nestedIndex[[1]],
index[[1]] + 1]]*projectionOperator[[index[[2]] + 1,nestedIndex[[2]]]]*projectionOperator[[
index[[3]] + 1,nestedIndex[[3]]]]*projectionOperator[[index[[4]] + 1,nestedIndex[[4]]]]*
spacetimeRiemannTensor[[nestedIndex[[1]],nestedIndex[[2]],nestedIndex[[3]],nestedIndex[[4]]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
4]]]; rightHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> spatialRiemannTensor[[index[[1]],index[[2]],index[[3]],index[[4]]]] +
mixedExtrinsicCurvatureTensor[[index[[1]],index[[3]]]]*extrinsicCurvatureTensor[[index[[2]],index[[4]]]] -
mixedExtrinsicCurvatureTensor[[index[[1]],index[[4]]]]*extrinsicCurvatureTensor[[index[[2]],index[[
3]]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 4]]];
Thread[Catenate[Catenate[Catenate[leftHandSide]]] == Catenate[Catenate[Catenate[rightHandSide]]]] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["CodazziMainardiEquations"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, mixedExtrinsicCurvatureTensor, extrinsicCurvatureTrace,
spacetimeMetricTensor, spacetimeChristoffelSymbols, spacetimeRiemannTensor, spacetimeRicciTensor, normalVector,
projectionOperator, leftHandSide, rightHandSide},
newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spatialChristoffelSymbols = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((1/2)*Inverse[newMatrixRepresentation][[index[[1]],#1]]*
(D[newMatrixRepresentation[[#1,index[[3]]]], newCoordinates[[index[[2]]]]] + D[newMatrixRepresentation[[
index[[2]],#1]], newCoordinates[[index[[3]]]]] - D[newMatrixRepresentation[[index[[2]],index[[3]]]],
newCoordinates[[#1]]]) & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 3]]]; extrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> (1/(2*newLapseFunction))*(D[shiftCovector[[First[index]]],
newCoordinates[[Last[index]]]] - Total[(spatialChristoffelSymbols[[#1,Last[index],First[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] + D[shiftCovector[[Last[index]]],
newCoordinates[[First[index]]]] - Total[(spatialChristoffelSymbols[[#1,First[index],Last[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] - D[newMatrixRepresentation[[
First[index],Last[index]]], newTimeCoordinate])] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
2]]]; mixedExtrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(Inverse[newMatrixRepresentation][[#1,Last[index]]]*
extrinsicCurvatureTensor[[First[index],#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; extrinsicCurvatureTrace =
Total[(Inverse[newMatrixRepresentation][[First[#1],Last[#1]]]*extrinsicCurvatureTensor[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]; spacetimeMetricTensor =
Normal[SparseArray[Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]] - newLapseFunction^2},
(Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
(Module[{index = #1}, {index + 1, 1} -> Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]]; spacetimeChristoffelSymbols =
Normal[SparseArray[(Module[{index = #1}, index -> Total[((1/2)*Inverse[spacetimeMetricTensor][[index[[1]],#1]]*
(D[spacetimeMetricTensor[[#1,index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[2]]]]] +
D[spacetimeMetricTensor[[index[[2]],#1]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] -
D[spacetimeMetricTensor[[index[[2]],index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[
#1]]]) & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 3]]]; spacetimeRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> D[spacetimeChristoffelSymbols[[index[[1]],index[[2]],index[[
4]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] - D[spacetimeChristoffelSymbols[[index[[
1]],index[[2]],index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[4]]]]] +
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[3]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[4]]]] & ) /@ Range[Length[spacetimeMetricTensor]]] -
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[4]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[3]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]]; spacetimeRicciTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(spacetimeRiemannTensor[[#1,First[index],#1,
Last[index]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
D[newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
projectionOperator = Normal[SparseArray[(Module[{index = #1}, index -> KroneckerDelta[First[index], Last[index]] +
Total[(normalVector[[Last[index]]]*spacetimeMetricTensor[[First[index],#1]]*normalVector[[#1]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
leftHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(D[mixedExtrinsicCurvatureTensor[[index,#1]], newCoordinates[[#1]]] & ) /@
Range[Length[newMatrixRepresentation]]] + Total[(spatialChristoffelSymbols[[First[#1],First[#1],Last[#1]]]*
mixedExtrinsicCurvatureTensor[[index,Last[#1]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
2]] - Total[(spatialChristoffelSymbols[[Last[#1],First[#1],index]]*mixedExtrinsicCurvatureTensor[[
Last[#1],First[#1]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 2]] -
D[extrinsicCurvatureTrace, newCoordinates[[index]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
rightHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((-spacetimeRicciTensor[[First[#1],Last[#1]]])*normalVector[[Last[#1]]]*
projectionOperator[[index + 1,First[#1]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]] & ) /@
Range[Length[newMatrixRepresentation]]]]; Thread[leftHandSide == rightHandSide] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["SymbolicCodazziMainardiEquations"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, mixedExtrinsicCurvatureTensor, extrinsicCurvatureTrace,
spacetimeMetricTensor, spacetimeChristoffelSymbols, spacetimeRiemannTensor, spacetimeRicciTensor, normalVector,
projectionOperator, leftHandSide, rightHandSide},
newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spatialChristoffelSymbols = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((1/2)*Inverse[newMatrixRepresentation][[index[[1]],#1]]*
(Inactive[D][newMatrixRepresentation[[#1,index[[3]]]], newCoordinates[[index[[2]]]]] +
Inactive[D][newMatrixRepresentation[[index[[2]],#1]], newCoordinates[[index[[3]]]]] -
Inactive[D][newMatrixRepresentation[[index[[2]],index[[3]]]], newCoordinates[[#1]]]) & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 3]]];
extrinsicCurvatureTensor = Normal[SparseArray[
(Module[{index = #1}, index -> (1/(2*newLapseFunction))*(Inactive[D][shiftCovector[[First[index]]],
newCoordinates[[Last[index]]]] - Total[(spatialChristoffelSymbols[[#1,Last[index],First[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] + Inactive[D][shiftCovector[[
Last[index]]], newCoordinates[[First[index]]]] - Total[(spatialChristoffelSymbols[[#1,First[index],
Last[index]]]*shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] -
Inactive[D][newMatrixRepresentation[[First[index],Last[index]]], newTimeCoordinate])] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; mixedExtrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(Inverse[newMatrixRepresentation][[#1,Last[index]]]*
extrinsicCurvatureTensor[[First[index],#1]] & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; extrinsicCurvatureTrace =
Total[(Inverse[newMatrixRepresentation][[First[#1],Last[#1]]]*extrinsicCurvatureTensor[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]; spacetimeMetricTensor =
Normal[SparseArray[Join[{{1, 1} -> Total[(newShiftVector[[#1]]*shiftCovector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]] - newLapseFunction^2},
(Module[{index = #1}, {1, index + 1} -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
(Module[{index = #1}, {index + 1, 1} -> Total[(newMatrixRepresentation[[#1,index]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]],
({First[#1] + 1, Last[#1] + 1} -> newMatrixRepresentation[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]]; spacetimeChristoffelSymbols =
Normal[SparseArray[(Module[{index = #1}, index -> Total[((1/2)*Inverse[spacetimeMetricTensor][[index[[1]],#1]]*
(Inactive[D][spacetimeMetricTensor[[#1,index[[3]]]], Join[{newTimeCoordinate}, newCoordinates][[
index[[2]]]]] + Inactive[D][spacetimeMetricTensor[[index[[2]],#1]], Join[{newTimeCoordinate},
newCoordinates][[index[[3]]]]] - Inactive[D][spacetimeMetricTensor[[index[[2]],index[[3]]]],
Join[{newTimeCoordinate}, newCoordinates][[#1]]]) & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 3]]]; spacetimeRiemannTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Inactive[D][spacetimeChristoffelSymbols[[index[[1]],index[[
2]],index[[4]]]], Join[{newTimeCoordinate}, newCoordinates][[index[[3]]]]] -
Inactive[D][spacetimeChristoffelSymbols[[index[[1]],index[[2]],index[[3]]]], Join[{newTimeCoordinate},
newCoordinates][[index[[4]]]]] + Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[3]]]]*
spacetimeChristoffelSymbols[[#1,index[[2]],index[[4]]]] & ) /@ Range[Length[spacetimeMetricTensor]]] -
Total[(spacetimeChristoffelSymbols[[index[[1]],#1,index[[4]]]]*spacetimeChristoffelSymbols[[#1,index[[2]],
index[[3]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 4]]]; spacetimeRicciTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(spacetimeRiemannTensor[[#1,First[index],#1,
Last[index]]] & ) /@ Range[Length[spacetimeMetricTensor]]]] & ) /@
Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
normalVector = Normal[SparseArray[
(Module[{index = #1}, index -> -Total[(newLapseFunction*Inverse[spacetimeMetricTensor][[index,#1]]*
Inactive[D][newTimeCoordinate, Join[{newTimeCoordinate}, newCoordinates][[#1]]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Range[Length[spacetimeMetricTensor]]]];
projectionOperator = Normal[SparseArray[(Module[{index = #1}, index -> KroneckerDelta[First[index], Last[index]] +
Total[(normalVector[[Last[index]]]*spacetimeMetricTensor[[First[index],#1]]*normalVector[[#1]] & ) /@ Range[
Length[spacetimeMetricTensor]]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]];
leftHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(Inactive[D][mixedExtrinsicCurvatureTensor[[index,#1]], newCoordinates[[
#1]]] & ) /@ Range[Length[newMatrixRepresentation]]] + Total[(spatialChristoffelSymbols[[First[#1],
First[#1],Last[#1]]]*mixedExtrinsicCurvatureTensor[[index,Last[#1]]] & ) /@ Tuples[
Range[Length[newMatrixRepresentation]], 2]] - Total[(spatialChristoffelSymbols[[Last[#1],First[#1],
index]]*mixedExtrinsicCurvatureTensor[[Last[#1],First[#1]]] & ) /@ Tuples[
Range[Length[newMatrixRepresentation]], 2]] - Inactive[D][extrinsicCurvatureTrace,
newCoordinates[[index]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
rightHandSide = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((-spacetimeRicciTensor[[First[#1],Last[#1]]])*normalVector[[Last[#1]]]*
projectionOperator[[index + 1,First[#1]]] & ) /@ Tuples[Range[Length[spacetimeMetricTensor]], 2]]] & ) /@
Range[Length[newMatrixRepresentation]]]]; Thread[leftHandSide == rightHandSide] /.
(ToExpression[#1] -> #1 & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ]] /;
SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["GeodesicSlicingCondition"] :=
lapseFunction == 1 /; SymbolName[metricTensor] === "MetricTensor" && Length[Dimensions[matrixRepresentation]] == 2 &&
Length[coordinates] == Length[matrixRepresentation] && BooleanQ[index1] && BooleanQ[index2] &&
Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["ReducedGeodesicSlicingCondition"] :=
FullSimplify[lapseFunction] == 1 /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2] && Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["MaximalSlicingCondition"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, contravariantExtrinsicCurvatureTensor, extrinsicCurvatureTrace,
lapseFunctionLaplacian}, newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newShiftVector =
shiftVector /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
shiftCovector = Normal[SparseArray[
(Module[{index = #1}, index -> Total[(newMatrixRepresentation[[index,#1]]*newShiftVector[[#1]] & ) /@
Range[Length[newMatrixRepresentation]]]] & ) /@ Range[Length[newMatrixRepresentation]]]];
spatialChristoffelSymbols = Normal[SparseArray[
(Module[{index = #1}, index -> Total[((1/2)*Inverse[newMatrixRepresentation][[index[[1]],#1]]*
(D[newMatrixRepresentation[[#1,index[[3]]]], newCoordinates[[index[[2]]]]] + D[newMatrixRepresentation[[
index[[2]],#1]], newCoordinates[[index[[3]]]]] - D[newMatrixRepresentation[[index[[2]],index[[3]]]],
newCoordinates[[#1]]]) & ) /@ Range[Length[newMatrixRepresentation]]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 3]]]; extrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> (1/(2*newLapseFunction))*(D[shiftCovector[[First[index]]],
newCoordinates[[Last[index]]]] - Total[(spatialChristoffelSymbols[[#1,Last[index],First[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] + D[shiftCovector[[Last[index]]],
newCoordinates[[First[index]]]] - Total[(spatialChristoffelSymbols[[#1,First[index],Last[index]]]*
shiftCovector[[#1]] & ) /@ Range[Length[newMatrixRepresentation]]] - D[newMatrixRepresentation[[
First[index],Last[index]]], newTimeCoordinate])] & ) /@ Tuples[Range[Length[newMatrixRepresentation]],
2]]]; contravariantExtrinsicCurvatureTensor =
Normal[SparseArray[(Module[{index = #1}, index -> Total[(Inverse[newMatrixRepresentation][[First[index],First[#1]]]*
Inverse[newMatrixRepresentation][[Last[#1],Last[index]]]*extrinsicCurvatureTensor[[First[#1],
Last[#1]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 2]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]]; extrinsicCurvatureTrace =
Total[(Inverse[newMatrixRepresentation][[First[#1],Last[#1]]]*extrinsicCurvatureTensor[[First[#1],Last[#1]]] & ) /@
Tuples[Range[Length[newMatrixRepresentation]], 2]]; lapseFunctionLaplacian =
Total[(Module[{index = #1}, (1/Sqrt[Det[newMatrixRepresentation]])*D[Sqrt[Det[newMatrixRepresentation]]*
Inverse[newMatrixRepresentation][[First[index],Last[index]]]*D[newLapseFunction, newCoordinates[[Last[
index]]]], newCoordinates[[First[index]]]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 2]];
lapseFunctionLaplacian == newLapseFunction*Total[(contravariantExtrinsicCurvatureTensor[[First[#1],Last[#1]]]*
extrinsicCurvatureTensor[[First[#1],Last[#1]]] & ) /@ Tuples[Range[Length[newMatrixRepresentation]], 2]] -
D[extrinsicCurvatureTrace, newTimeCoordinate] /. (ToExpression[#1] -> #1 & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]] /; SymbolName[metricTensor] === "MetricTensor" &&
Length[Dimensions[matrixRepresentation]] == 2 && Length[coordinates] == Length[matrixRepresentation] &&
BooleanQ[index1] && BooleanQ[index2] && Length[shiftVector] == Length[matrixRepresentation]
ADMDecomposition[(metricTensor_)[matrixRepresentation_List, coordinates_List, index1_, index2_], timeCoordinate_,
lapseFunction_, shiftVector_List]["ReducedMaximalSlicingCondition"] :=
Module[{newMatrixRepresentation, newCoordinates, newTimeCoordinate, newLapseFunction, newShiftVector, shiftCovector,
spatialChristoffelSymbols, extrinsicCurvatureTensor, contravariantExtrinsicCurvatureTensor, extrinsicCurvatureTrace,
lapseFunctionLaplacian}, newMatrixRepresentation = matrixRepresentation /. (#1 -> ToExpression[#1] & ) /@
Select[Join[coordinates, {timeCoordinate}], StringQ]; newCoordinates =
coordinates /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}], StringQ];
newTimeCoordinate = timeCoordinate /. (#1 -> ToExpression[#1] & ) /@ Select[Join[coordinates, {timeCoordinate}],
StringQ]; newLapseFunction = lapseFunction /. (#1 -> ToExpression[#1] & ) /@