This note contains a set of six theorems that can be used to assess the ability of a theorem-proving system to reason about equality. The six theorems are graduated in terms of difficulty: they range from fairly trivial to quite difficult. They do not cover all aspects of equality reasoning, but they have proved useful to us in developing our system.

}, url = {http://www.springerlink.com/content/p4kx51623661hu77/}, author = {Ewing L. Lusk and R. A. Overbeek} }