ACTA issues

Conditions for the prefix expansion of a monoid to be (weakly) left ample

Christopher Hollings

Acta Sci. Math. (Szeged) 73:3-4(2007), 519-545

Abstract. We derive necessary and sufficient conditions for the Birget--Rhodes prefix expansion [BR1] of a monoid to be (weakly) left ample, thereby proving analogues of the results already obtained for the related Szendrei expansion by Fountain, Gomes and Gould [FGG] and Fountain and Gomes [FG]. As a corollary, we obtain conditions for the prefix expansion to be inverse.

AMS Subject Classification (1991): 20M99

Keyword(s): prefix expansion, (weakly) left ample monoid, inverse monoid

Received October 31, 2006, and in final form March 15, 2007. (Registered under 6450/2009.)