Modular and Certified Semantic Labeling and Unlabeling

Christian Sternagel & René Thiemann
Semantic labeling is a powerful transformation technique to prove termination of term rewrite systems. The dual technique is unlabeling. For unlabeling it is essential to drop the so called decreasing rules which sometimes have to be added when applying semantic labeling. We indicate two problems concerning unlabeling and present our solutions. The first problem is that currently unlabeling cannot be applied as a modular step, since the decreasing rules are determined by a semantic labeling...