A note on decidability questions on presentations of word semigroups
: Choffrut C, Harju T, Karhumaki J
Publisher: ELSEVIER SCIENCE BV
: 1997
: Theoretical Computer Science
: THEORETICAL COMPUTER SCIENCE
: THEOR COMPUT SCI
: 183
: 1
: 83
: 92
: 10
: 0304-3975
DOI: https://doi.org/10.1016/S0304-3975(96)00311-8
We apply automata-theoretic tools and some recently established compactness properties in the study of F-semigroups, that is, subsemigroups of free semigroups. With each F-semigroup we associate an F-presentation, which turns out to be finite for all finitely generated F-semigroups. Connections between F-presentations and ordinary presentations of semigroups are pointed out. It is also shown that it is undecidable whether two finitely generated F-semigroups satisfy a common relation in their F-presentations.