Outermost ground termination
Résumé
We propose a semi-automatic inductive process to prove termination of outermost rewriting on ground term algebras. The method is based on an abstraction mechanism, schematizing normalisation of subterms, and on narrowing, schematizing reductions on ground terms. The induction ordering is not needed a priori, but is a solution of constraints set along the proof. Our method applies in particular to systems that are non-terminating for the standard strategy nor even for the lazy strategy.