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Title
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Weak cost register automata are still powerful
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Author
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Abstract
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| We consider one of the weakest variants of cost register automata over a tropical semiring, namely copyless cost register automata over N with updates using min and increments. We show that this model can simulate, in some sense, the runs of counter machines with zero-tests. We deduce that a number of problems pertaining to that model are undecidable, namely equivalence, upperboundedness, and semilinearity. In particular, the undecidability of equivalence disproves a conjecture of Alur et al. from 2012. To emphasize how weak these machines are, we also show that they can be expressed as a restricted form of linearly-ambiguous weighted automata. |
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Language
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English
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Source (journal)
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International journal of foundations of computer science. - Singapore
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Publication
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Singapore
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2020
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ISSN
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0129-0541
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DOI
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10.1142/S0129054120410026
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Volume/pages
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31
:6
(2020)
, p. 689-709
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ISI
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000599907100003
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Full text (Publisher's DOI)
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Full text (open access)
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