Modular properties of conditional term rewriting systems
Aart Middeldorp · Data Archiving and Networked Services (DANS) · 1991
A property of term rewriting systems is called modular if it is preserved under disjoint union. For unconditional term rewriting systems several modularity results are known. The aim of this paper is to analyze and extend these results to conditional term rewriting systems. It turns out that conditional term rewriting is much more complicated than unconditional rewriting from a modularity point of view. For instance, we show that the modularity of weak normalization for unconditional term rewriting systems does not extend to conditional term rewriting systems. On the positive side, we mention the extension of Toyama?s confluence result for disjoint unions of term rewriting systems to conditional term rewriting.