(theory-equal-p <thing1> <thing2> [<implementation>])
Predicate for testing whether <thing1> and <thing2> refer to the same theory. <thing1> and <thing2> may be any object acceptable to FIND-THEORY; if either of them is not a theory object then <implementation> will be examined to determine which implementation of the specified theory to consider. <implementation> should be a symbol (usually a keyword); if unspecified, the current implementation is will be assumed (see IN-IMPLEMENTATION.)