Journal of Algebra, Number Theory: Advances and ApplicationsAuthor's: Jiangping Xiao and Yonghua Li
Pages: [111] - [126]
Received Date: December 13, 2014
Submitted by:
A left U-semiadequate semigroup is a left U-semiabundant
semigroup whose projections commute. Let 
be a left U-semiadequate semigroup.
It is the fact that each 
of contains a unique projection. For an
element a of 
the projection in the containing a is denoted by 
If satisfying left ample condition (AL), then
we say that is a left U-ample semigroup. In this
paper, we introduce the concept of a proper cover of a left
U-ample semigroup and prove that any proper cover for a left
U-ample semigroup is a proper cover over a monoid. A structure
theorem of proper covers for left U-ample semigroups is
obtained. This theorem generalizes the result of Guo-Xie for left type
A semigroups.
left U-ample semigroup, proper cover, monoid.
