Gomes, G.M.S. and Gould, V. (2008) Finite proper covers in a class of finite semi-groups with commuting idempotents. Semigroup Forum, 66 (3). pp. 433-454. ISSN 1432-2137
Weakly left ample semigroups are a class of semigroups that are (2,1) -subalgebras of semigroups of partial transformations, where the unary operation takes a transformation α to the identity map in the domain of α . It is known that there is a class of proper weakly left ample semigroups whose structure is determined by unipotent monoids acting on semilattices or categories. In this paper we show that for every finite weakly left ample semigroup S , there is a finite proper weakly left ample semigroup and an onto morphism from S to S which separates idempotents. In fact, S is actually a (2,1) -subalgebra of a symmetric inverse semigroup, that is, it is a left ample semigroup (formerly, left type A).
|Institution:||The University of York|
|Academic Units:||The University of York > Mathematics (York)|
|Depositing User:||York RAE Import|
|Date Deposited:||12 Feb 2009 17:23|
|Last Modified:||12 Feb 2009 17:23|
|Publisher:||Springer Verlag (Germany)|