Algebraic & Geometric Topology

Exotic iterated Dehn twists

Paul Seidel

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Consider cotangent bundles of exotic spheres with their canonical symplectic structure. They admit automorphisms that preserve the part at infinity of one fiber and which are analogous to the square of a Dehn twist. Pursuing that analogy, we show that they have infinite order up to isotopy (inside the group of all automorphisms with the same behavior).

Article information

Algebr. Geom. Topol., Volume 14, Number 6 (2014), 3305-3324.

Received: 22 May 2013
Revised: 15 October 2013
Accepted: 16 March 2014
First available in Project Euclid: 19 December 2017

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Mathematical Reviews number (MathSciNet)

Zentralblatt MATH identifier

Primary: 53D40: Floer homology and cohomology, symplectic aspects 57S05: Topological properties of groups of homeomorphisms or diffeomorphisms

exotic sphere symplectic automorphism Floer homology


Seidel, Paul. Exotic iterated Dehn twists. Algebr. Geom. Topol. 14 (2014), no. 6, 3305--3324. doi:10.2140/agt.2014.14.3305.

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