Relationships




Parents 
constant quantity 
A ConstantQuantity is a PhysicalQuantity that has a constant value, e.g. 3 Meters and 5 HourDurations. The magnitude (see MagnitudeFn) of every ConstantQuantity is a RealNumber. ConstantQuantity is distinguished from FunctionQuantity, in that each instance of the latter is formed through the mapping of one PhysicalQuantity to another PhysicalQuantity. Each instance of ConstantQuantity is expressed with the BinaryFunction MeasureFn, which takes a Number and a UnitOfMeasure as arguments. For example, 3 Meters is expressed as (MeasureFn 3 Meter). Instances of ConstantQuantity form a partial order (see PartialOrderingRelation) with the lessThan relation, since lessThan is a RelationExtendedToQuantities and lessThan is defined over the RealNumbers. The lessThan relation is not a total order (see TotalOrderingRelation) over the class ConstantQuantity since elements of some subclasses of ConstantQuantity (such as length quantities) are incomparable to elements of other subclasses of ConstantQuantity (such as mass quantities).


unit of measure 
A standard of measurement for some dimension. For example, the Meter is a UnitOfMeasure for the dimension of length, as is the Inch. There is no intrinsic property of a UnitOfMeasure that makes it primitive or fundamental, rather, a system of units (e.g. SystemeInternationalUnit) defines a set of orthogonal dimensions and assigns units for each.

Children 
UnitOfAngularMeasure  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of AngleMeasure. 
 UnitOfCurrency  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of CurrencyMeasure. 
 UnitOfDuration  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of TimeDuration. Note that TimeDuration is a subclass of TimeMeasure. 
 UnitOfInformation  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of InformationMeasure. 
 UnitOfLength  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of LengthMeasure. 
 UnitOfMass  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of MassMeasure, which denote the amount of matter in PhysicalObjects. 
 UnitOfTemperature  Every instance of this Class is a UnitOfMeasure that can be used with MeasureFn to form instances of TemperatureMeasure. 