6533b853fe1ef96bd12acd5b

RESEARCH PRODUCT

Verbal sets and cyclic coverings

Giovanni CutoloChiara Nicotera

subject

Discrete mathematicsCommutatorgroup wordAlgebra and Number TheorySubgroup coveringscommutatorComputer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing)Central seriescoveringSet (abstract data type)Verbal subgroupsVerbal subgroupCharacteristic subgroupGroup theoryLower central seriesFinite setWord (group theory)Group theoryCyclic subgroupsMathematics

description

Abstract We consider groups G such that the set of all values of a fixed word w in G is covered by a finite set of cyclic subgroups. Fernandez-Alcober and Shumyatsky studied such groups in the case when w is the word [ x 1 , x 2 ] , and proved that in this case the corresponding verbal subgroup G ′ is either cyclic or finite. Answering a question asked by them, we show that this is far from being the general rule. However, we prove a weaker form of their result in the case when w is either a lower commutator word or a non-commutator word, showing that in the given hypothesis the verbal subgroup w ( G ) must be finite-by-cyclic. Even this weaker conclusion is not universally valid: it fails for verbose words.

10.1016/j.jalgebra.2010.06.025http://dx.doi.org/10.1016/j.jalgebra.2010.06.025