The main aim of this paper is to describe the closure of a finitely generated subgroup of a finitely generated free group in the proabelian topology. Our approach depends heavily on the description of the abelian kernel of a finite inverse semigroup.

中文翻译：

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阿贝尔核、有限拓扑和扩展问题

本文的主要目的是描述概率拓扑中有限生成自由群的有限生成子群的闭包。我们的方法在很大程度上取决于对有限逆半群的阿贝尔核的描述。