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Stallings foldings and the subgroup structure of free groups

Ilya Kapovich·Alexei Myasnikov
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Abstract

We re-cast in a more combinatorial and computational form the foldings approach of John Stallings and pursue a detailed study of the subgroup structure of free groups. In particular, we introduce the notions of an "algebraic" and a "free" extension for subgroups of free groups and apply these notions to obtain a number of algebraic and algorithmic results.

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Ilya Kapovich, Alexei Myasnikov. 2002-02-27. Stallings foldings and the subgroup structure of free groups. https://arxiv.org/abs/math/0202285

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