Semigroups that are factors of subdirectly irreducible semigroups by their monolith

被引:3
|
作者
Bulman-Fleming, S [1 ]
Hotzel, E
Wang, J
机构
[1] Wilfrid Laurier Univ, Dept Math, Waterloo, ON N2L 3C5, Canada
[2] Univ Windsor, Dept Math & Stat, Windsor, ON N9B 3P4, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
semigroup; subdirectly irreducible; monolith;
D O I
10.1007/s00012-004-1823-y
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Jezek and Kepka [4] proved that a universal algebra A with at least one at least binary operation is isomorphic to the factor of a subdirectly irreducible algebra B by its monolith if and only if the intersection of all of its (nonempty) ideals is nonempty, and that B may be chosen to be finite if A is finite. (By an ideal of A is meant a non-empty subset I of A such that f(a(1)_ _a(n)) is an element of I whenever f is an n-ary fundamental operation of A and a(1),...,a(n) is an element of A are elements with a(i) is an element of I for at least one index i.) In the present paper, we prove that if A is a semigroup, then B may be chosen also to be a semigroup, but that a finite semigroup need not be isomorphic to the factor of a finite subdirectly irreducible semigroup by its monolith.
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页码:1 / 7
页数:7
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