关于左(右)分式半群(Ⅱ)

ON THE LEFT (RIGHT) SEMIGROUP OF FRACTIONS(Ⅱ)

是[1]的继续,给出了半群A相对于A的子半群S的左(右)分式半群的泛性质和唯一性,证明了:如果A相对于S的左、右分式半群都存在,则它们是同构的,另外还证明了若干半群类在取左(右)分式半群下是封闭的。

This paper is a continuation of [1]. Let A be a semigroup and let S be a subsemigroup of A. It give the universal property and the uniqueness of the left (right) semigroup of fractions of A with respect to S and prove that the left and right semigroups of fractions of A with respect to S are isomorphic if both of them exist. More—over, some classes of semigroups are closed when taking left (right) semigroups of fractions.