Post Embedding Problem Is Not Primitive Recursive, with Applications to Channel Systems
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چکیده
We introduce PEP, the Post Embedding Problem, a variant of PCP where one compares strings with the subword relation, and PEPreg, a further variant where solutions are constrained and must belong to a given regular language. PEPreg is decidable but not primitive recursive. This entails the decidability of reachability for unidirectional systems with one reliable and one lossy channel.
منابع مشابه
Subwords: automata, embedding problems, and verification
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تاریخ انتشار 2007