Summary: The notion of operational termination captures nonterminating computations due to subsidiary processes that are necessary to issue a single ‘main’ step but which often remain ‘hidden’ when the main computation sequence is observed. This highlights two dimensions of nontermination: one for the infinite sequencing of computation steps, and the other that concerns the proof of some single steps. For conditional term rewriting systems (CTRSs), we introduce a new dependency pair framework which exploits the bidimensional nature of conditional rewriting (rewriting steps + satisfaction of the conditions as reachability problems) to obtain a powerful and more expressive framework for proving operational termination of CTRSs.
For the entire collection see [Zbl 1318.68016].