"Equivalence (mathematics)" is an unlikely candidate for an article. Actually, all such equivalences are examples of an equivalence relation or its generalizations beyond the set theory (such as canonically isomorphic objects in the category theory). "Equivalence" in mathematical parlance does not specify any definite relation on a set or so – there are many cases where "up to equivalence" is used implicitly, and the appropriate wikilink has to be not a generally-nonsensical "Equivalence (mathematics)", but an article about a more concrete implementation of equivalence relation.