On Problems Dual to Unification
Zümrüt Akçam, Daniel S. Hono, Paliath Narendran · arXiv (Cornell University) · 2017
In this paper, we investigate a problem dual to the unification problem, namely the Common Term (CT) problem for string rewriting systems. Our main motivation was in computing fixed points in systems, such as loop invariants in programming languages. We show that the fixed point problem is reducible to the common term problem. We also prove that the common term problem is undecidable for dwindling string rewriting systems.