有限对称逆半群的类A子半群

A Type A Subsemigroup of Finite Symmetric Inverse Semigroup

设In是集Xn={1,2,…,n}上的对称逆半群.设σ■Xn×Xn 且σ={(n,n—1),…,(3,2),(2,1)}.令Iσ={α∈In: x,y∈dom α,(x,y)∈σ■(xα,yα)∈σ}∪{(φ)},在此证得Iσ是In的一个类A子半群,进一步研究了Iσ上的Green*关系.

Let In be the symmetric inverse subsemigroup on the set Xn = {1,2,…,n}, and let σlohtain in Xn×Xn and σ= {（n,n -1）,…,（3,2）,（2,1）}. LetIσ={α∈In： x,y∈dom α,（x,y）∈σ=〉（xa,ya）∈σ）∪{Φ}. In this paper we obtain that Iσ is a type A subsemigroup of In, and inverstigate the Green＇s＊ relations of Iσ.