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arXiv · 1505.00478

Proving Looping and Non-Looping Non-Termination by Finite Automata

Jörg Endrullis·Hans Zantema
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Abstract

A new technique is presented to prove non-termination of term rewriting. The basic idea is to find a non-empty regular language of terms that is closed under rewriting and does not contain normal forms. It is automated by representing the language by a tree automaton with a fixed number of states, and expressing the mentioned requirements in a SAT formula. Satisfiability of this formula implies non-termination. Our approach succeeds for many examples where all earlier techniques fail, for instance for the S-rule from combinatory logic.

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Jörg Endrullis, Hans Zantema. 2015-05-03. Proving Looping and Non-Looping Non-Termination by Finite Automata. https://arxiv.org/abs/1505.00478

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