YAP (was Re: Proposal: Remove Show and Eq superclasses of Num)

[Paterson, Ross]

Tyson Whitehead writes:
> It would, therefore, seem to me that the key observation this encoding
> is expressing is that two elements being being factors of each other
> implies they are nessesarily related by an invertable multiple.
>
> I guess then that the set of associates is also completely characterized
> as any of its elements multiplied by all unit (invertable) elements.

Yes.  It's the arbitrariness in the selection of the representative that
some object to.  (But we do need a representative.)