Grid Structures and Undecidable Constraint Theories ?
نویسندگان
چکیده
We express conditions for a term to be a nite grid-like structure. Together with deenitions of term properties by excluding \forbid-den patterns" we obtain three new undecidability results in three areas: the 9 8-fragment of the theory of one-step rewriting for linear and shallow rewrite systems, the emptiness for automata with equality tests between rst cousins (i.e. only tests at depth 2 below the current node are available), and the 9 8-fragment of the theory of set constraints.
منابع مشابه
Grid Structure and Undecidable Constraint Theories
We prove three new undecidability results for computational mechanisms over nite trees: There is a linear, ultra-shallow, noetherian and strongly connuent rewrite system R such that the 9 8-fragment of the rst-order theory of one-step-rewriting by R is undecidable; the emptiness problem for tree automata with equality tests between cousins is undecidable; and the 9 8-fragment of the rst-order t...
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تاریخ انتشار 1997