88 search results - page 5 / 18 » Computing automorphisms of semigroups |
COCOON
2003
Springer
15 years 2 months ago
2003
Springer
Abstract. We show that finding roots of Boolean matrices is an NPhard problem. This answers a twenty year old question from semigroup theory. Interpreting Boolean matrices as dire...
STACS
2005
Springer
15 years 2 months ago
2005
Springer
FOCS
1990
IEEE
15 years 1 months ago
1990
IEEE
The exponent of periodicity is an important factor in estimates of complexity of word-unification algorithms. We prove that the exponent of periodicity of a minimal solution of a w...
DCC
2006
IEEE
15 years 9 months ago
2006
IEEE
We determine all linear codes C containing the constant code E, for which there is a weight-preserving group of semilinear automorphisms which acts transitively on the set of nont...