2018/04/17 by Almagor, Shaull, Cadilhac, Michaël, Mazowiecki, Filip +1 · 1 citation
#FOS: Computer and information sciences #Formal Languages and Automata Theory (cs.FL)
paper · doi:10.48550/arxiv.1804.06336
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, in particular equivalence, disproving 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.