Unification in Conditional Equational Theories

A complete unification procedure for confluent conditional term rewriting systems is presented which is a generalization of the narrowing process described by Fay and Hullot. Neither the finite termination property nor syntactical restrictions on conditions are needed. The algorithm can be seen as a new functional logic programming technique, too. The unification procedure has been built into the RAP system, a system supporting rapid prototyping for algebraic specifications.