The free splitting complex of a free group I: Hyperbolicity

Abstract

We prove that the free splitting complex of a finite rank free group, also known as Hatcher's sphere complex, is hyperbolic.

85 pages, including index and glossary. Many figures in the free splitting complex, in the guise of commutative diagrams of maps between free splittings. Changes from Version 1 to Version 2: Corrected an error in the proof of Proposition 6.5, Step 2. Revamped the theory of free splitting units in Section 5

References in corpus (1)

• On the geometry of a proposed curve complex analogue for $Out(F_n)$

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