Asynchronous Multi-Tape Automata Intersection: Undecidability and Approximation
Abstract
When their reading heads are allowed to move completely asynchronously, finite-state automata with multiple tapes achieve a significant expressive power, but also lose useful closure properties---closure under intersection, in particular. This paper investigates to what extent it is still feasible to use multi-tape automata as recognizer of polyadic predicates on words. On the negative side, determining whether the intersection of asynchronous multi-tape automata is expressible is not even semidecidable. On the positive side, we present an algorithm that computes under-approximations of the intersection; and discuss simple conditions under which it can construct complete intersections. A prototype implementation and a few non-trivial examples demonstrate the algorithm in practice.
Keywords
Cite
@article{arxiv.1206.4860,
title = {Asynchronous Multi-Tape Automata Intersection: Undecidability and Approximation},
author = {Carlo A. Furia},
journal= {arXiv preprint arXiv:1206.4860},
year = {2014}
}