16 Mar
2011
16 Mar
'11
8:04 a.m.
Pragmatically you might want two classes - AdditiveGroup and MultiplicativeGroup. There is a lot of work in this area such as the NumericPrelude on Hackage and Jerzy Karczmarczuk's paper "Functional Programming and Mathematical Objects" [link below]. Numeric hierarchies expose problems for Haskell's class system, hence everyone complains about the Num classes but no-one has been able to fix them. http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.32.3328