English

Equivalence Testing of Weighted Automata over Partially Commutative Monoids

Formal Languages and Automata Theory 2020-06-02 v2

Abstract

We study \emph{multiplicity equivalence} testing of automata over partially commutative monoids (pc monoids) and show efficient algorithms in special cases, exploiting the structure of the underlying non-commutation graph of the monoid. Specifically, if the clique cover number of the non-commutation graph (the minimum number of cliques covering the graph) of the pc monoid is a constant, we obtain a deterministic quasi-polynomial time algorithm. As a consequence, we also obtain the first deterministic quasi-polynomial time algorithms for multiplicity equivalence testing of kk-tape automata and for equivalence testing of deterministic kk-tape automata for constant kk. Prior to this, a randomized polynomial-time algorithm for the above problems was shown by Worrell [ICALP 2013]. We also consider pc monoids for which the non-commutation graphs have cover consisting of at most kk cliques and star graphs for any constant kk. We obtain randomized polynomial-time algorithm for multiplicity equivalence testing of automata over such monoids.

Keywords

Cite

@article{arxiv.2002.08633,
  title  = {Equivalence Testing of Weighted Automata over Partially Commutative Monoids},
  author = {V. Arvind and Abhranil Chatterjee and Rajit Datta and Partha Mukhopadhyay},
  journal= {arXiv preprint arXiv:2002.08633},
  year   = {2020}
}