A class of weakly U-abundant semigroups satisfying the congruence condition （C） is investigated, which contains both the class of regular semigroups and the class of abundant semigroups as its subclasses. In particu...A class of weakly U-abundant semigroups satisfying the congruence condition （C） is investigated, which contains both the class of regular semigroups and the class of abundant semigroups as its subclasses. In particular, the class of weakly U-abundant semigroups satisfying the congruence condition （C） with Ehresmann transversals is studied. After giving some properties of U-abundant semigroups with Ehresmann transversals, we establish some characterization theorems for such semigroups. Our results may be regarded as an extension of the work of Blyth, McAlister and McFadden in regular semigroups and that of El-Qallali, Guo and Chen in abundant semigroups.展开更多
A semigroup S with a sub-band B is called a good B-quasi-Ehresmann semigroup if it is a Bsemiabundant semigroup satisfying the congruence condition such that B((ab)+)abB((ab)*)aB(a*)B(b+)b for all a,b ∈S.We show that...A semigroup S with a sub-band B is called a good B-quasi-Ehresmann semigroup if it is a Bsemiabundant semigroup satisfying the congruence condition such that B((ab)+)abB((ab)*)aB(a*)B(b+)b for all a,b ∈S.We show that every good B-quasi-Ehresmann semigroup has a global representation and a standard representation.As a special case,the structure of good quasi-adequate semigroups is described.展开更多
基金The research is supported by the Natural Science Foundation of China （11471255, 61672416）, Special Research Fundation of Education Department of Shaanxi Province （15JK1411）, Natural Science Basic Research Project in Shaanxi Province of China （2015JQ1006） and Basic Research Foundation of Xi＇an University of Architecture and Technology （JC1416）.
文摘A class of weakly U-abundant semigroups satisfying the congruence condition （C） is investigated, which contains both the class of regular semigroups and the class of abundant semigroups as its subclasses. In particular, the class of weakly U-abundant semigroups satisfying the congruence condition （C） with Ehresmann transversals is studied. After giving some properties of U-abundant semigroups with Ehresmann transversals, we establish some characterization theorems for such semigroups. Our results may be regarded as an extension of the work of Blyth, McAlister and McFadden in regular semigroups and that of El-Qallali, Guo and Chen in abundant semigroups.
基金supported by National Basic Research Program of China (Grant No.2003CB317001)Natural Science Foundation of Hunan (Grant No.06JJ20025)+1 种基金Scientific Research Fund of HunanProvincial Education Department (Grant No.09K084)UGC (HK) (Grant No.2160210 (03/04))
文摘A semigroup S with a sub-band B is called a good B-quasi-Ehresmann semigroup if it is a Bsemiabundant semigroup satisfying the congruence condition such that B((ab)+)abB((ab)*)aB(a*)B(b+)b for all a,b ∈S.We show that every good B-quasi-Ehresmann semigroup has a global representation and a standard representation.As a special case,the structure of good quasi-adequate semigroups is described.
