摘要
设X为任意的非空集合,T X是X上的全变换半群.设E是X上的一个等价关系,T E*(X)是由等价关系E所决定的T X的子半群,满足(x,y)∈E当且仅当(f(x),(fy))∈E.将讨论T E*(X)中的变换在自然偏序关系下的覆盖元以及任意两个变换的上(下)界.
Let X be an arbitrary nonempty set,T X is the full transformation semigroup on X. Let E be an equivalence relation on X,T E*(X)is a subsemigroup of T X determined by E which satisfies(x,y)∈E if and only if(f(x),(fy))∈E. In this paper,the covering elements of T E*(X)under the natural order are described,and the lowe(rupper)bound of two elements is discussed.
引文
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