Submission date: 11 March 2009.

Abstract:

We consider embeddings in a torsion-free hyperbolic group which are elementary in the sense of first-order logic. We give a description of these embeddings in terms of Sela's hyperbolic towers. We deduce as a corollary that subgroups elementarily embedded in finitely generated free groups are free factors.

Mathematics Subject Classification: 20F67 (Primary) 20E05, 03C07 (Secondary)

Keywords and phrases:

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