Properties or qualities as distinguished from any particular embodiment of the properties/qualities in a physical medium. Instances of Abstract can be said to exist in the same sense as mathematical objects such as sets and relations, but they cannot exist at a particular place and time without some physical encoding or embodiment.
||FiniteQuantity||Any Quantity that is limited or bounded in magnitude.|
| ||InfiniteQuantity||Any Quantity that is not limited or bounded in magnitude.|
| ||MultipoleQuantity||a multipole variable that have physical dimension and meaning.|
| ||Number||A measure of how many things there are, or how much there is, of a certain kind. Numbers are subclassed into RealNumber, ComplexNumber, and ImaginaryNumber.|
| ||PhysicalDimension||A physical dimension such as length, mass, force etc.|
| ||PhysicalQuantity||A PhysicalQuantity is a measure of some quantifiable aspect of the modeled world, such as 'the earth's diameter' (a constant length) and 'the stress in a loaded deformable solid' (a measure of stress, which is a function of three spatial coordinates). Every PhysicalQuantity is either a ConstantQuantity or FunctionQuantity. Instances of ConstantQuantity are dependent on a UnitOfMeasure, while instances of FunctionQuantity are Functions that map instances of ConstantQuantity to other instances of ConstantQuantity (e.g., a TimeDependentQuantity is a FunctionQuantity). Although the name and definition of PhysicalQuantity is borrowed from physics, a PhysicalQuantity need not be material. Aside from the dimensions of length, time, velocity, etc., nonphysical dimensions such as currency are also possible. Accordingly, amounts of money would be instances of PhysicalQuantity. A PhysicalQuantity is distinguished from a pure Number by the fact that the former is associated with a dimension of measurement.|