摘要
设Λ是任意的非空集合,Γ是集合Λ上的半格,PΓ(Λ×Λ)是集合Λ上的半格Γ确定的二元关系半群.利用半格的性质,讨论了半群PΓ(Λ×Λ)的最大左单位;通过左单位的构造方法,获得了半群PΓ(Λ×Λ)的左单位是唯一左单位的充分必要条件.
Let Λ be an arbitrary nonempty set and Γ be a semilattice on the set Λ,and then PΓ( Λ×Λ) is a semigroup of binary relations determined by the semilattice Γ on the set Λ. The greatest left unit in the semigroup PΓ( Λ×Λ) is discussed with reference to the properties of semilattice. The necessary and sufficient condition for the greatest left unit of the semigroup PΓ( Λ×Λ) to be the unique left unit is obtained according to the construction of the left unit.
引文
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