A Floer homology for exact contact embeddings

Abstract

In this paper we construct the Floer homology for an action functional which was introduced by Rabinowitz and prove a vanishing theorem. As an application, we show that there are no displaceable exact contact embeddings of the unit cotangent bundle of a sphere of dimension greater than three into a convex exact symplectic manifold with vanishing first Chern class. This generalizes Gromov's result that there are no exact Lagrangian embeddings of a sphere into ‫ރ‬ n .

Rabinowitz Floer homology and symplectic homology

“…If c 1 (V ) = 0 they are Z-graded, and if c 1 (V ) vanishes on π 2 (V ) the part constructed from contractible loops is Z-graded. This Zgrading on Rabinowitz Floer homology differs from the one in [9] (which takes values in 1 2 + Z) by a shift of 1/2 (see Remark 3.2).…”

“…The first two authors have recently defined for such an exact contact embedding Floer homology groups RF H * (M, W ) for the Rabinowitz action functional [9]. We refer to Section 3 for a recap of the definition and of some useful properties.…”

“…If c 1 (V ) = 0 they are Z-graded, and if c 1 (V ) vanishes on π 2 (V ) the part constructed from contractible loops is Z-graded. This Zgrading on Rabinowitz Floer homology differs from the one in [9] (which takes values in Our purpose is to relate these two constructions. The relevant object is a new version of symplectic homology, denotedŠH * (V ), associated to " -shaped" Hamiltonians like the one in Figure 1 on page 20 below.…”

“…One can classically [25] associate to such an exact contact embedding the symplectic (co)homology groups SH * (V ) and SH * (V ). We The first two authors have recently defined for such an exact contact embedding Floer homology groups RF H * (M, W ) for the Rabinowitz action functional [9]. We refer to Section 3 for a recap of the definition and of some useful properties.…”

“…. .We also recall the following vanishing result for Rabinowitz Floer homology from [9].To state the next corollary, we recall that the symplectic (co)homology and Rabinowitz Floer homology groups decompose as direct sumsc * (V ) indexed over free homotopy classes of loops in V . We denote the free homotopy class of the constant loops by c = 0.…”