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# constant quantity (ConstantQuantity)

A ConstantQuantity is a PhysicalQuantity which has a constant value, e.g. 3 meters and 5 hours. The magnitude (see MagnitudeFn) of every ConstantQuantity is a RealNumber. ConstantQuantities are distinguished from FunctionQuantities, which map ConstantQuantities to other ConstantQuantities. All ConstantQuantites are expressed with the BinaryFunction MeasureFn, which takes a Number and a UnitOfMeasure as arguments. For example, 3 Meters can be expressed as (MeasureFn 3 Meter). ConstantQuantities 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).

## Ontology

SUMO / BASE-ONTOLOGY

## Superclass(es)

 entity

abstract

quantity

physical quantity

constant quantity

## Subclass(es)

time measure  length measure  mass measure  area measure  volume measure  temperature measure  currency measure  angle measure  information measure

## Coordinate term(s)

function quantity  unit of measure

## Constrains relations

interval fn  magnitude fn  measure fn

## Related WordNet synsets

See more related synsets on a separate page.

## Axioms (2)

physical quantity is exhaustively partitioned into constant quantity,function quantity.
`(partition PhysicalQuantity ConstantQuantity FunctionQuantity)`

If function is an instance of unary constant functionquantity, then the number argument of function is an instance of constant quantity and range of function is an instance of constant quantity.
```(=>
(instance ?FUNCTION UnaryConstantFunctionQuantity)
(and
(domain ?FUNCTION 1 ConstantQuantity)
(range ?FUNCTION ConstantQuantity)))```