Lambda-Confluence Is Undecidable for Clearing Restarting Automata

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F13%3A10145557" target="_blank" >RIV/00216208:11320/13:10145557 - isvavai.cz</a>
Result on the web
<a href="http://dx.doi.org/10.1007/978-3-642-39274-0_23" target="_blank" >http://dx.doi.org/10.1007/978-3-642-39274-0_23</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1007/978-3-642-39274-0_23" target="_blank" >10.1007/978-3-642-39274-0_23</a>

Result language
angličtina
Original language name
Lambda-Confluence Is Undecidable for Clearing Restarting Automata
Original language description
Clearing restarting automata are based on contextual rewriting. A word w is accepted by an automaton of this type if there is a computation that reduces the word w to the empty word Î}} by a finite sequence of rewritings. Accordingly, the word problem for a clearing restarting automaton can be solved nondeterministically in quadratic time. If, however, the contextual rewritings happen to be Î}}-confluent, that is, confluent on the congruence class of the empty word, then the word problem can be solved deterministically in linear time. Here we show that, unfortunately, Î}}-confluence is not even recursively enumerable for clearing restarting automata. This follows from the fact that Î}}-confluence is not recursively enumerable for finite factor-erasingstring-rewriting systems.
Czech name
—
Czech description
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Project
<a href="/en/project/GAP103%2F10%2F0783" target="_blank" >GAP103/10/0783: Structure and its impact for recognition</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2013
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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