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We extend a recent result that for the (additive) semigroup of positive integers , there are continuum many subdirect products of up to isomorphism. We prove that for each one of (the group of integers), (the monoid of non-negative integers), or , we prove that has continuum many (semigroup) subdirect products up to isomorphism.

生成讲解博客的中文版本

生成AI智能校验的中文版本