Abstract
Toyama's Theorem states that confluence is a modular property of disjoint term rewriting systems. This theorem does not generalize to combined systems with shared constructors. Thus the question arises naturally whether there are sufficient conditions which ensure the modularity of confluence in the presence of shared constructors. In particular, Kurihara and Krishna Rao posed the problem whether there arc interesting sufficient conditions independent of termination. This question appeared as Problem 59 in the list of open problems in the theory of rewriting published recently [DJK93]. The present paper gives an affirmative answer to that question. Among other sufficient criteria, it is shown that confluence is preserved under the combination of constructorsharing systems if the systems arc also normalizing. This in conjunction with the fact that normalization is modular for those systems implies the modularity of semi-completeness.
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References
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© 1994 Springer-Verlag Berlin Heidelberg
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Ohlebusch, E. (1994). On the modularity of confluence of constructor-sharing term rewriting systems. In: Tison, S. (eds) Trees in Algebra and Programming — CAAP'94. CAAP 1994. Lecture Notes in Computer Science, vol 787. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0017487
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DOI: https://doi.org/10.1007/BFb0017487
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