For an infinite set X, denote by Ω(X) the semigroup of all surjective mappings from X to X. We determine Green's relations in Ω(X), show that the kernel (unique minimum ideal) of Ω(X) exists and det ermine its ...For an infinite set X, denote by Ω(X) the semigroup of all surjective mappings from X to X. We determine Green's relations in Ω(X), show that the kernel (unique minimum ideal) of Ω(X) exists and det ermine its elemen ts and cardinali ty. For a cou ntably infinite set X, we describe the elements of Ω(X) for which the D-class and J-class coincide. We compare the results for Ω(X) with the corresponding results for other transformation semigroups on X.展开更多
文摘For an infinite set X, denote by Ω(X) the semigroup of all surjective mappings from X to X. We determine Green's relations in Ω(X), show that the kernel (unique minimum ideal) of Ω(X) exists and det ermine its elemen ts and cardinali ty. For a cou ntably infinite set X, we describe the elements of Ω(X) for which the D-class and J-class coincide. We compare the results for Ω(X) with the corresponding results for other transformation semigroups on X.
