arXiv subjects

Yildiray Ozan

Publications and source records attributed to Yildiray Ozan.

4 recordsLinked to original sources

arXiv2006

Trace Homomorphism for Smooth Manifolds

Let $M$ be a closed connected smooth manifold and $G=\textmd{Diff}_0(M)$ denote the connected component of the diffeomorphism group of $M$ containing the identity. The natural action of $G$ on $M$ induces the trace homomorphism on homology. We show that the image of trace homomorphism is annihilated by the subalgebra of the cohomology ring of $M$, generated by the characteristic classes of $M$. Analogously, if $J$ is an almost complex structure on $M$ and $G$ denotes the identity component of the group of diffeomorphisms of $M$ preserving $J$ then the image of the corresponding trace homomorphism is annihilated by subalgebra generated by the Chern classes of $(M,J)$.

math.GT↗

arXiv2006

Triviality of symplectic SU(2)-actions on homology

Lalonde and McDuff showed that the natural action of the rational homology of the group of Hamiltonian diffeomorphisms of a closed symplectic manifold $(M, ω)$ on the rational homology groups $H_*(M,{\mathbb Q})$ is trivial. In this note, given a symplectic action of SU(2), $ϕ:SU(2)\times M \to M$, we will construct a symplectic fiber bundle $P_ϕ\to {\mathbb CP}^2$ with fiber $(M,ω)$ and use it to construct the chains, which bound the images of the homology cycles under the trace map given by the SU(2)-action. It turns out that the natural chains bounded by the SU(2)-orbits in $M$ are punctured ${\mathbb CP}^2$'s, the counter parts of holomorphic discs bounding circles in case of Hamiltonian circle actions. We will also define some invariants of the action $ϕ$ and do some explicit calculations.

math.SG↗

arXiv2005

On cohomology of invariant submanifolds of Hamiltonian actions

In this note we prove the following theorem: Let $G$ be a compact Lie group acting on a compact symplectic manifold $M$ in a Hamiltonian fashion. If $L$ is an $l$-dimensional closed invariant submanifold of $M$, on which the $G$-action is locally free then the fundamental class $[L]$ is trivial in $H_l(M,{\mathbb Q})$. We also prove similar results for lower homology groups of $L$, in case the group $G$ is a finite product of copies of $S^1$ and SU(2). The key ingredients of the proofs are Kirwan's theorem that Hamiltonian spaces are equivariantly formal and symplectic reduction.

math.SG↗

arXiv2004

Relative Flux Homomorphism in Symplectic Geometry

In this work we define a relative version of the flux homomorphism, introduced by Calabi in 1969, for a symplectic manifold. We use it to study (the universal cover of) the group of symplectomorphisms of a symplectic manifold leaving a Lagrangian submanifold invariant. We show that some quotients of this group are stable under symplectic reduction.

math.SG↗