This closes issue #49 (closed). Some remarks:
TopSet, which corresponds with
SetUnfoldElemOf for any
Hint Resolve coPset_top_subseteq : core no longer works because the lemma is generic in a type class. AFAIK it is only used for
solve_ndisjoint, so I added a specialized version to the
ndisj hint database. We already have specialized versions of other set lemmas there.