SI_Functions1.ocd

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<CDComment>

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Author: Joseph B. Collins (2009), Naval Research Laboratory, Washington, DC.
Copyright Notice:  This is a work of the U.S. Government and is not
subject to copyright protection in the United States. Foreign copyrights
may apply.

</CDComment>

  <CDName>SI_functions1</CDName>
  <CDBase>http://www.openmath.org/cd</CDBase>
  <CDURL>http://www.openmath.org/cd/SI_functions1.ocd</CDURL>
  <CDReviewDate>2017-12-31</CDReviewDate>
  <CDStatus>experimental</CDStatus>
  <CDDate>2009-01-10</CDDate>
  <CDVersion>1</CDVersion>
  <CDRevision>1</CDRevision>
<CDComment>
  Author: J B Collins
</CDComment>

  <Description> 
    This CD defines symbols for functions applied to SI quantities and
    units.
  </Description>

  <CDDefinition>
    <Name>dim</Name>
    <Role>application</Role>
    <Description> 
      The symbol to represent the function that returns the physical
      dimension of its argument in terms of products of powers of
      SI base quantities. The dim operation may be meaningfully applied to SI
      quantities, SI units, and numbers without physical dimension.
    </Description>
    <CMP> The dim operator acts as the identity operation when applied to
    an SI base quantity.</CMP>
    <CMP> The dim operator returns the corresponding SI base quantity when
    applied to an SI base unit.</CMP>
    <CMP> For named SI derived quantities and named units, the value returned
    by the dim operator shall be defined for each case.</CMP>
    <CMP> The dim operator applied to a product is equal to the associative
    product of the dim operator applied to the individual factors. </CMP>
    <CMP> The dim operator applied to a product is equal to the commutative
    product of the dim operator applied to the factors. </CMP>
    <CMP> The dim operator applied to a multiplicative inverse of a
    quantity is equal to the multiplicative inverse of the dim operator
    applied to the same quantity. </CMP>
    <CMP> The dim operator returns a value of one when applied to a
    dimensionless quantity or number.</CMP>
  </CDDefinition>

  <CDDefinition>
    <Name>unit</Name>
    <Role>application</Role>
    <Description> 
      The symbol to represent the function that returns the units
      of its argument in terms of a product of powers of
      SI base units.
    </Description>
    <CMP>The unit operator may be applied to any physical quantity.</CMP>
    <CMP>The unit operator applied to an SI base quantity returns the
    corresponding SI base unit.</CMP>
    <CMP>The unit operator applied to an SI base unit or SI coherent unit
    acts as the identity operator, returning that unit.</CMP>
    <CMP>The unit operator applied to any derived quantity is equal to the 
    unit operator applied to the result of applying the dim operator to the
    same quantity, i.e., unit(Q) = unit(dim(Q)). </CMP>
    <CMP> The unit operator applied to a product is equal to the
    commutative product of the unit operator applied to the factors.</CMP>
    <CMP> The unit operator applied to a product is equal to the
    associative product of the unit operator applied to the factors.</CMP>
    <CMP> The unit operator applied to a multiplicative inverse of a
    quantity is equal to the multiplicative inverse of the unit operator
    applied to the same quantity. </CMP>
    <CMP> The unit operator returns a value of one when applied to a
    dimensionless quantity or number.</CMP>
  </CDDefinition>

  <CDDefinition>
    <Name>num</Name>
    <Role>application</Role>
    <Description> 
      The symbol to represent the function to return the numerical
      value of a quantity in terms of a product of powers of
      SI base units.
    </Description>
    <CMP>The num operator may be applied to any physical quantity.</CMP>
    <CMP>The num operator applied to an SI base quantity or unit returns
    the value one.</CMP>
    <CMP> The quantity num(Q)*unit(Q), may replace any quantity, Q, in
    a set of physical relations, if all such quantities in the set of
    relations are so replaced. The quantity num(Q)*unit(Q) is not always
    the same as Q, however dim(Q) = dim(num(Q)*unit(Q)).</CMP>
  </CDDefinition>

  <CDDefinition>
    <Name>kind</Name>
    <Role>application</Role>
    <Description> 
      The symbol to represent the function to return the kind
      of a quantity. The value of this function is referred to, but not
      defined in the SI. Its value, kind(Q) for a given quantity, Q, is
      left to the user to assign.
    </Description>
  </CDDefinition>

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