Automata, Languages, and Machines
Automata, Languages, and Machines
A context-free and a 1-counter geodesic language for a Baumslag-Solitar group
Theoretical Computer Science
Word problems recognisable by deterministic blind monoid automata
Theoretical Computer Science
Semigroup automata with rational initial and terminal sets
Theoretical Computer Science
Hi-index | 5.23 |
We prove that a group G has a word problem that is accepted by a deterministic counter automaton with a weak inverse property if and only if G is virtually abelian. We extend this result to larger classes of groups by considering a generalization of finite state automata, counter automata and pushdown automata. Natural corollaries of our general result include a restricted version of Herbst's classification of groups for which the word problem is a one counter language and a new classification of automata that accept context-free word problems.