Easy multiplications. I. The realm of Kleene's theorem
Information and Computation
Journal of Computer and System Sciences
Easy multiplications. II. extensions of rational semigroups
Information and Computation
Group presentations, formal languages and characterizations of one-counter groups
Theoretical Computer Science
Semigroups and Combinatorial Applications
Semigroups and Combinatorial Applications
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
Introduction to Formal Language Theory
Introduction to Formal Language Theory
The Mathematical Theory of Context-Free Languages
The Mathematical Theory of Context-Free Languages
Hi-index | 0.00 |
The word problem is of fundamental interest in group theory and has been widely studied. One important connection between group theory and theoretical computer science has been the consideration of the word problem as a formal language; a pivotal result here is the classification by Muller and Schupp of groups with a context-free word problem. Duncan and Gilman have proposed a natural extension of the notion of the word problem as a formal language from groups to semigroups and the question as to which semigroups have a context-free word problem then arises. Whilst the depth of the Muller-Schupp result and its reliance on the geometrical structure of Cayley graphs of groups suggests that a generalization to semigroups could be very hard to obtain we have been able to prove some results about this intriguing class of semigroups.