Scalable and Continuous

A brief idea: something like... -- class (Additive a) => Scalable a scale :: Real -> a -> a -- equivalent to * (not sure of name for Real type) class (Scalable b) => Continuous a b | a -> b add :: b -> a -> a difference :: a -> a -> b -- Vectors, for instance, are Scalable. You can multiply them by any real number to get another vector. Num would also be Scalable. An example of Continuous would be time, e.g. "Continuous Time Interval". There's no zero time, although there is a zero interval. Space too: "Continuous Position Displacement", since there's no "zero position". -- Ashley Yakeley, Seattle WA