scholarly journals Unique normal form property of compatible term rewriting systems: a new proof of Chew's theorem

2001 ◽  
Vol 258 (1-2) ◽  
pp. 169-208
Author(s):  
Ken Mano ◽  
Mizuhito Ogawa
2008 ◽  
Vol 11 (2) ◽  
Author(s):  
Andre Luiz Galdino ◽  
Mauricio Ayala Rincon

A theory for Abstract Reduction Systems (ARS) in the proof assistant PVS (Prototype Verification System) called ars is described. Adequate specifications of basic definitions and notions of the theory of ARSs such as reduction, confluence and normal form are given and well-known results formalized. The formalizations include non trivial results of the theory of ARSs such as the correctness of the principle of Noetherian Induction, Newman’s Lemma and its generalizations, and Commutation Lemmas, among others. Although term rewriting proving technologies have been provided in several specification languages and proof assistants, to our knowledge, before the development presented in this paper there was no complete formalization of an abstract reduction theory in PVS. This makes relevant the presented ars specification as the basis of a PVStheory called trs for the general treatment of Term Rewriting Systems.


2002 ◽  
Vol 13 (06) ◽  
pp. 873-887
Author(s):  
NADIA NEDJAH ◽  
LUIZA DE MACEDO MOURELLE

We compile pattern matching for overlapping patterns in term rewriting systems into a minimal, tree matching automata. The use of directed acyclic graphs that shares all the isomorphic subautomata allows us to reduce space requirements. These are duplicated in the tree automaton. We design an efficient method to identify such subautomata and avoid duplicating their construction while generating the dag automaton. We compute some bounds on the size of the automata, thereby improving on previously known equivalent bounds for the tree automaton.


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