A quantity function maps some objects to a quantity.
(<= (Range $X Time-Dependent-Quantity) (Quantity-Function $X)) (=> (Quantity-Function ?Qf) (Range ?Qf Time-Dependent-Quantity)) (Nth-Domain Quantity-Function-Dimension 2 Quantity-Function) (<=> (Quantity-Function-Dimension ?Class ?Function ?Dimension) (And (Class ?Class) (Quantity-Function ?Function) (Physical-Dimension ?Dimension) (Forall (?X) (=> (Instance-Of ?X ?Class) (= (Quantity.Dimension (Value ?Function ?X)) ?Dimension))))) (=> (Has-Quantity-Function $X $Y) (Quantity-Function $Y)) (=> (Quantity-Function-Total-On $X $Y) (Quantity-Function $X)) (<=> (Quantity-Function-Total-On ?Quantity-Function ?Class) (And (Quantity-Function ?Quantity-Function) (Class ?Class) (Total-On ?Quantity-Function ?Class)))