So I was trying to work through MATH-1416, which is to remove code from CM which has been moved to CN and I ran into a snag when trying to replace o.a.c.math4.f.BigFraction with the version from CN in the KolmogorovSmirnovTest class. This class uses o.a.c.m.f.BigFraction as an implementation of FieldElement which o.a.c.n.f.BigFraction is not since FieldElement is in CM and not in CN.
I started down the road of creating an extension of o.a.c.numbers.f.BigFraction which implemented FieldElement, but that started to get sticky and complex and did not feel like the right answer. I seems like the right answer is to move Field, FieldElement and RealFieldElement into numbers and then BigFraction, Fraction, etc. can implement FieldElement again. This would mean no awkward bridge code to stuff o.a.c.numbers.f.BigFraction into a FieldElement implementation. Re terminology a field is an abstract system of numbers so I don't see an issue there. Following the existing convention I would create a commons-numbers-field submodule for the moved classes. Any objections?
