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Formality of canonical symplectic complexes and Frobenius manifolds
math.SG
It is shown that the de Rham complex of a symplectic manifold $M$ satisfying the hard Lefschetz condition is formal. Moreover, it is shown that the differential Gerstenhaber-Batalin-Vilkoviski algebra associated to such a symplectic structure gives rise, along the lines explained in the papers of Barannikov and Kontsev...
math
2,901
Almost Complex Structures on $S^2\times S^2$
math.SG
In this note we investigate the structure of the space $\Jj$ of smooth almost complex structures on $S^2\times S^2$ that are compatible with some symplectic form. This space has a natural stratification that changes as the cohomology class of the form changes and whose properties are very closely connected to the topol...
math
2,902
A Note on Higher Cohomology Groups of Kähler Quotients
math.SG
Consider a holomorphic torus action on a possibly non-compact K\"ahler manifold. We show that the higher cohomology groups appearing in the geometric quantization of the symplectic quotient are isomorphic to the invariant parts of the corresponding cohomology groups of the original manifold. For non-Abelian group actio...
math
2,903
On existence of nonformal simply connected symplectic manifolds
math.SG
Examples of nonformal simply connected symplectic manifolds are constructed.
math
2,904
A limit of toric symplectic forms that has no periodic Hamiltonians
math.SG
We calculate the Riemann-Roch number of some of the pentagon spaces defined in [Klyachko,Kapovich-Millson,HK1]. Using this, we show that while the regular pentagon space is diffeomorphic to a toric variety, even symplectomorphic to one under arbitrarily small perturbations of its symplectic structure, it does not admit...
math
2,905
On nonformal simply connected symplectic manifolds
math.SG
For any $N \geq 5$ nonformal simply connected symplectic manifolds of dimension $2N$ are constructed. This disproves the formality conjecture for simply connected symplectic manifolds which was introduced by Lupton and Oprea.
math
2,906
A Note on n-ary Poisson Brackets
math.SG
A class of n-ary Poisson structures of constant rank is indicated. Then, one proves that the ternary Poisson brackets are exactly those which are defined by a decomposable 3-vector field. The key point is the proof of a lemma which tells that an n-vector $(n\geq3)$ is decomposable iff all its contractions with up to n-...
math
2,907
Graded Lagrangian submanifolds
math.SG
In the usual setup, the grading on Floer homology is relative: it is unique only up to adding a constant. "Graded Lagrangian submanifolds" are Lagrangian submanifolds with a bit of extra structure, which fixes the ambiguity in the grading. The idea is originally due to Kontsevich. This paper contains an exposition of t...
math
2,908
Stability for holomorphic spheres and Morse theory
math.SG
In this paper we study the question of when does a closed, simply connected, integral symplectic manifold (W,omega) have the stability property for its spaces of based holomorphic spheres? This property states that in a stable limit under certain gluing operators, the space of based holomorphic maps from a sphere to X,...
math
2,909
A note on generating functions
math.SG
An afinne-invariant view of generating functions of symplectic transformations of an affine symplectic space is discussed. More generally, it works for symmetric symplectic spaces. The note is completely elementary, but it yields some nice pictures.
math
2,910
Completely integrable systems: a generalization
math.SG
We present a slight generalization of the notion of completely integrable systems to get them being integrable by quadratures. We use this generalization to integrate dynamical systems on double Lie groups.
math
2,911
Lefschetz fibrations and the Hodge bundle
math.SG
Integral symplectic 4-manifolds may be described in terms of Lefschetz fibrations. In this note we give a formula for the signature of any Lefschetz fibration in terms of the second cohomology of the moduli space of stable curves. As a consequence we see that the sphere in moduli space defined by any (not necessarily h...
math
2,912
Classical dynamical r-matrices and homogeneous Poisson structures on $G/H$ and $K/T$
math.SG
Let G be a finite dimensional simple complex group equipped with the standard Poisson Lie group structure. We show that all G-homogeneous (holomorphic) Poisson structures on $G/H$, where $H \subset G$ is a Cartan subgroup, come from solutions to the Classical Dynamical Yang-Baxter equations which are classified by Etin...
math
2,913
Construction of completely integrable systems by Poisson mappings
math.SG
Pulling back sets of functions in involution by Poisson mappings and adding Casimir functions during the process allows to construct completely integrable systems. Some examples are investigated in detail.
math
2,914
Integrable Hamiltonian systems on Lie groups: Kowalevski type
math.SG
The contributions of Sophya Kowalewski to the integrability theory of the equations for the heavy top extend to a larger class of Hamiltonian systems on Lie groups; this paper explains these extensions, and along the way reveals further geometric significance of her work in the theory of elliptic curves. Specifically, ...
math
2,915
The structure of a symplectic manifold on the space of loops of 7-manifold
math.SG
We define a symplectic structure on the space of non parametrized loops in $G_2$ manifold. We also develop some basics of intersection theory of Lagrangian submanifolds.
math
2,916
Remarks on the flux groups
math.SG
I study flux groups of compact symplectic manifolds. Under some topological assumptions, I give a new estimate of the rank of flux groups and give a method of construcion of compact symplectic aspherical manifolds.
math
2,917
Transversality theory, cobordisms, and invariants of symplectic quotients
math.SG
This paper gives methods for understanding invariants of symplectic quotients. The symplectic quotients considered here are compact symplectic manifolds (or more generally orbifolds), which arise as the symplectic quotients of a symplectic manifold by a compact torus. (A companion paper examines symplectic quotients by...
math
2,918
Symplectic quotients by a nonabelian group and by its maximal torus
math.SG
This paper examines the relationship between the symplectic quotient X//G of a Hamiltonian G-manifold X, and the associated symplectic quotient X//T, where T is a maximal torus, in the case in which X//G is a compact manifold or orbifold. The three main results are: a formula expressing the rational cohomology ring o...
math
2,919
On Symplectically Harmonic Forms on Six-dimensional Nilmanifolds
math.SG
In the present paper we study the variation of the dimensions $h_k$ of spaces of symplectically harmonic cohomology classes (in the sense of Brylinski) on closed symplectic manifolds. We give a description of such variation for all 6-dimensional nilmanifolds equipped with symplectic forms. In particular, it turns out t...
math
2,920
On certain geometric and homotopy properties of closed symplectic manifolds
math.SG
The paper deals with relations between the Hard Lefschetz property, (non)vanishing of Massey products and the evenness of odd-degree Betti numbers of closed symplectic manifolds. It is known that closed symplectic manifolds can violate all these properties (in contrast with the case of Kaehler manifolds). However, the ...
math
2,921
Quantization of bending deformations of polygons in Euclidean space, hypergeometric integrals and the Gassner representation
math.SG
We quantize the bending deformations of n-gon linkages by linearizing the bending fields at a degenerate n-gon to get a representation of the Malcev Lie algebra of the pure braid group. This linearization yields a flat connection on the space of n distinct points on the complex line. We show that the monodromy is (esse...
math
2,922
Loops of Lagrangian submanifolds and pseudoholomorphic discs
math.SG
The main theorem of this paper asserts that the inclusion of the space of projective Lagrangian planes into the space of Lagrangian submanifolds of complex projective space induces an injective homomorphism of fundamental groups. We introduce three invariants of exact loops of Lagrangian submanifolds that are modelled ...
math
2,923
Convexity of multi-valued momentum map
math.SG
We extend the famous convexity theorem of Atiyah, Guillemin and Sternberg to the case of non-Hamiltonian actions. We show that the image of a generalized momentum map is a bounded polytope times a vector space. We prove that this picture is stable for small perturbations of the symplectic form. We also observe that an ...
math
2,924
Holomorphic Disks and the Chord Conjecture
math.SG
We prove (a weak version of) Arnold's Chord Conjecture using Gromov's ``classical'' idea in to produce holomorphic disks with boundary on a Lagrangian submanifold.
math
2,925
Locally Lagrangian Symplectic and Poisson Manifolds
math.SG
We discuss symplectic manifolds where, locally, the structure is that encountered in Lagrangian dynamics. Exemples and characteristic properties are given. Then, we refer to the computation of the Maslov classes of a Lagrangian submanifold. Finally, we indicate the generalization of this type of structures to Poisson m...
math
2,926
Coupling Tensors and Poisson Geometry Near a Single Symplectic Leaf
math.SG
In the framework of the connection theory, a contravariant analog of the Sternberg coupling procedure is developed for studying a natural class of Poisson structures on fiber bundles, called coupling tensors. We show that every Poisson structure near a closed symplectic leaf can be realized as a coupling tensor. Our ma...
math
2,927
The Topological Structure of Contact and Symplectic Quotients
math.SG
We show that if a Lie group acts properly on a co-oriented contact manifold preserving the contact structure, then the contact quotient is topologically a stratified space (in the sense that a neighborhood of a point in the quotient is a product of a disk with a cone on a compact stratified space). As a corollary, we o...
math
2,928
Hamiltonian symplectomorphisms and the Berry phase
math.SG
On the space ${\cal L}$, of loops in the group of Hamiltonian symplectomorphisms of a symplectic quantizable manifold, we define a closed ${\bf Z}$-valued 1-form $\Omega$. If $\Omega$ vanishes, the prequantization map can be extended to a group representation. On ${\cal L}$ one can define an action integral as an ${\bf...
math
2,929
Homotopy type of symplectomorphism groups of S^2 X S^2
math.SG
In this paper we discuss the topology of the symplectomorphism group of a product of two 2-dimensional spheres when the ratio of their areas lies in the interval (1,2]. More precisely we compute the homotopy type of this symplectomorphism group and we also show that the group contains two finite dimensional Lie groups ...
math
2,930
Symplectomorphism groups and almost complex structures
math.SG
This paper studies groups of symplectomorphisms of ruled surfaces for symplectic forms with varying cohomology class. This class is characterized by the ratio R of the size of the base to that of the fiber. By considering appropriate spaces of almost complex structures, we investigate how the topological type of these ...
math
2,931
Symplectic Structures on Fiber Bundles
math.SG
Let $\pi: P\to B$ be a locally trivial fiber bundle over a connected CW complex $B$ with fiber equal to the closed symplectic manifold $(M,\om)$. Then $\pi$ is said to be a symplectic fiber bundle if its structural group is the group of symplectomorphisms $\Symp(M,\om)$, and is called Hamiltonian if this group may be r...
math
2,932
Cohomological properties of ruled symplectic structures
math.SG
This survey presents some recent results by the authors and Polterovich on the topological properties of ruled symplectic manifolds. The bundle M \to P \to B that is associated with a ruled manifold has the group of Hamiltonian symplectomorphisms of M as structure group if the base is simply connected. Thus information...
math
2,933
Sets of singular restrictions of symplectic forms
math.SG
Let $\Omega$ be a non-singular syplectic form on some vector space $V$. Denote by $S^{n}_{k}(\Omega)$ the set of all $k$-dimensional planes $s$ in $V$ such that the restriction of $\Omega$ onto $s$ is singular. For the cases when $k=2,n-2$ a simple geometric characteristic of $S^{n}_{k}(\Omega)$ will be described.
math
2,934
Lefschetz pencils and divisors in moduli space
math.SG
We study Lefschetz pencils on symplectic four-manifolds via the associated spheres in the moduli spaces of curves, and in particular their intersections with certain natural divisors. An invariant defined from such intersection numbers can distinguish manifolds with torsion first Chern class. We prove that pencils of l...
math
2,935
Geometric monodromy and the hyperbolic disc
math.SG
Symplectic four-manifolds give rise to Lefschetz fibrations, which are determined by monodromy representations of free groups in mapping class groups. We study the topology of Lefschetz fibrations by analysing the action of the monodromy on the universal cover of a smooth fibre. We give new and simple proofs that Lefsc...
math
2,936
Hofer-Zehnder capacity and length minimizing Hamiltonian paths
math.SG
We use the criteria of Lalonde and McDuff to show that a path that is generated by a generic autonomous Hamiltonian is length minimizing with respect to the Hofer norm among all homotopic paths provided that it induces no non-constant closed trajectories in M. This generalizes a result of Hofer for symplectomorphisms o...
math
2,937
On bilinear invariant differential operators acting on tensor fields on the symplectic manifold
math.SG
Let $M$ be an $n$-dimensional manifold, $V$ the space of a representation $\rho: GL(n)\longrightarrow GL(V)$. Locally, let $T(V)$ be the space of sections of the tensor bundle with fiber $V$ over a sufficiently small open set $U\subset M$, in other words, $T(V)$ is the space of tensor fields of type $V$ on $M$ on which...
math
2,938
Coherent Orientations in Symplectic Field Theory
math.SG
We study the coherent orientations of the moduli spaces of holomorphic curves in Symplectic Field Theory, generalizing a construction due to Floer and Hofer. In particular we examine their behavior at multiple closed Reeb orbits under change of the asymptotic direction. The orientations are determined by a certain choi...
math
2,939
Geometric variants of the Hofer norm
math.SG
This note discusses some geometrically defined seminorms on the group $\Ham(M, \omega)$ of Hamiltonian diffeomorphisms of a closed symplectic manifold $(M, \omega)$, giving conditions under which they are nondegenerate and explaining their relation to the Hofer norm. As a consequence we show that if an element in $\Ham...
math
2,940
Symplectically aspherical manifolds
math.SG
The main subjects of the paper is studying the fundamental groups of closed symplectically aspherical manifolds. Motivated by some results of Gompf, we introduce two classes of fundamental groups $\pi_1(M)$ of symplectically aspherical manifolds $M$ with $\pi_2(M)=0$ and $\pi_2(M)\neq 0$. Relations between these classe...
math
2,941
Action integrals along closed isotopies in coadjoint orbits
math.SG
Let ${\cal O}$ be the orbit of $\eta\in{\frak g}^*$ under the coadjoint action of the compact Lie group $G$. We give two formulae for calculating the action integral along a closed Hamiltonian isotopy on ${\cal O}$. The first one expresses this action in terms of a particular character of the isotropy subgroup of $\eta...
math
2,942
Chain level Floer theory and Hofer's geometry of the Hamiltonian diffeomorphism group
math.SG
In this paper we first apply the chain level Floer theory to the study of Hofer's geometry of Hamiltonian diffeomorphism group in the cases without quantum contribution: we prove that any quasi-autonomous Hamiltonian path on weakly exact symplectic manifolds or any autonomous Hamiltonian path on arbitrary symplectic ma...
math
2,943
Some title containing the words "homotopy" and "symplectic", e.g. this one
math.SG
Using a basic idea of Sullivan's rational homotopy theory, one can see a Lie groupoid as the fundamental groupoid of its Lie algebroid. This paper studies analogues of Lie algebroids with non-trivial higher homotopy. Using various homotopy classes one can obtain e.g. central extensions of loop groups, or one can integr...
math
2,944
A long exact sequence for symplectic Floer cohomology
math.SG
The long exact sequence describes how the Floer cohomology of two Lagrangian submanifolds changes if one of them is modified by applying a Dehn twist. We give a proof in the simplest case (no bubbling). The paper contains a certain amount of material that may be of interest independently of the exact sequence: in parti...
math
2,945
How to (symplectically) thread the eye of a (Lagrangian) needle
math.SG
We show that there exists no Lagrangian embeddings of the Klein bottle into $\CC^{2}$. Using the same techniques we also give a new proof that any Lagrangian torus in $\CC^2$ is smoothly isotopic to the Clifford torus.
math
2,946
Gromov-Witten invariants of symplectic quotients and adiabatic limits
math.SG
We study pseudoholomorphic curves in symplectic quotients as adiabatic limits of solutions of a system of nonlinear first order elliptic partial differential equations in the ambient symplectic manifold. The symplectic manifold carries a Hamiltonian group action. The equations involve the Cauchy-Riemann operator over a...
math
2,947
The equivariant cohomology of Hamiltonian $G$-spaces From Residual $S^1$ Actions
math.SG
We show that for a Hamiltonian action of a compact torus $G$ on a compact, connected symplectic manifold $M$, the $G$-equivariant cohomology is determined by the residual $S^1$ action on the submanifolds of $M$ fixed by codimension-1 tori. This theorem allows us to compute the equivariant cohomology of certain manifold...
math
2,948
Propagation in Hamiltonian dynamics and relative symplectic homology
math.SG
The main result asserts the existence of noncontractible periodic orbits for compactly supported time dependent Hamiltonian systems on the unit cotangent bundle of the torus or of a negatively curved manifold whenever the generating Hamiltonian is sufficiently large over the zero section. The proof is based on Floer ho...
math
2,949
Bending flows for sums of rank one matrices
math.SG
We study certain symplectic quotients of n-fold products of complex projective m-space by the unitary group acting diagonally. After studying nonemptiness and smoothness these quotients we construct the action-angle variables, defined on an open dense subset of an integrable Hamiltonian system. The semiclassical quanti...
math
2,950
An effective algorithm for the cohomology ring of symplectic reductions
math.SG
Let G be a compact torus acting on a compact symplectic manifold M in a Hamiltonian fashion, and T a subtorus of G. We prove that the kernel of $\kappa:H_G^*(M)\to H^*(M//G)$ is generated by a small number of classes $\alpha\in H_G^*(M)$ satisfying very explicit restriction properties. Our main tool is the equivariant ...
math
2,951
Grafting Seiberg-Witten monopoles
math.SG
We demonstrate that the operation of taking disjoint unions of J-holomorphic curves (and thus obtaining new J-holomorphic curves) has a Seiberg-Witten counterpart. The main theorem asserts that, given two solutions (A_i, psi_i), i=0,1 of the Seiberg-Witten equations for the Spin^c-structure W^+_{E_i}= E_i direct sum (E...
math
2,952
A classification of topologically stable Poisson structures on a compact oriented surface
math.SG
Poisson structures vanishing linearly on a set of smooth closed disjoint curves are generic in the set of all Poisson structures on a compact connected oriented surface. We construct a complete set of invariants classifying these structures up to an orientation-preserving Poisson isomorphism. We show that there is a se...
math
2,953
Symplectically harmonic cohomology of nilmanifolds
math.SG
This paper can be considered as an extension to our paper [On symplectically harmonic forms on six-dimensional nilmanifolds, Comment. Math. Helv. 76 (2001), n 1, 89-109]. Also, it contains a brief survey of recent results on symplectically harmonic cohomology.
math
2,954
Symplectic action around loops in $\text{Ham}(M)$
math.SG
Let $\text{Ham(M)}$ be the group of Hamiltonian symplectomorphisms of a quantizable, compact, symplectic manifold $(M,\omega)$. We prove the existence of an action integral around loops in $\text{Ham(M)}$, and determine the value of this action integral on particular loops when the manifold is a coadjoint orbit.
math
2,955
The Chord Problem and a new method of filling by pseudoholomorphic curves
math.SG
In this paper we give a simple application of the filling methods developed earlier to the chord problem in three dimensional contact geometry.
math
2,956
The symplectic vortex equations and invariants of Hamiltonian group actions
math.SG
In this paper we define invariants of Hamiltonian group actions for central regular values of the moment map. The key hypotheses are that the moment map is proper and that the ambient manifold is symplectically aspherical. The invariants are based on the symplectic vortex equations. Applications include an existence th...
math
2,957
Codimension one symplectic foliations
math.SG
We define the concept of symplectic foliation on a symplectic manifold and provide a method of constructing many examples, by using asymptotically holomorphic techniques.
math
2,958
Cohomology rings of symplectic quotients by circle actions
math.SG
In this article we are concerned with how to compute the cohomology ring of a symplectic quotient by a circle action using the information we have about the cohomology of the original manifold and some data at the fixed point set of the action. Our method is based on the Tolman-Weitsman theorem which gives a characteri...
math
2,959
An extension theorem in symplectic geometry
math.SG
We extend the ``Extension after Restriction Principle'' for symplectic embeddings of bounded starlike domains to a large class of symplectic embeddings of unbounded starlike domains.
math
2,960
On a question of Dusa McDuff
math.SG
Consider the $2n$-dimensional closed ball $B$ of radius 1 in the $2n$-dimensional symplectic cylinder $Z = D \times R^{2n-2}$ over the closed disc $D$ of radius 1. We construct for each $\epsilon >0$ a Hamiltonian deformation $\phi$ of $B$ in $Z$ of energy less than $\epsilon$ such that the area of each intersection of...
math
2,961
Lectures on Groups of Symplectomorphisms
math.SG
These notes combine material from short lecture courses given in Paris, France, in July 2001 and in Srni, the Czech Republic, in January 2003. They discuss groups of symplectomorphisms of closed symplectic manifolds (M,\om) from various points of view. Lectures 1 and 2 provide an overview of our current knowledge of th...
math
2,962
Geodesic flows and contact toric manifolds
math.SG
These are notes for a course on contact manifolds and torus actions delivered at the summer school on Symplectic Geometry of Integrable Hamiltonian Systems at Centre de Recerca Matem\`atica in Barcelona in July 2001. To be published by Birkhauser.
math
2,963
Enumerative vs. Symplectic Invariants and Obstruction Bundles
math.SG
We give detailed descriptions of gluing pseudoholomorphic maps in symplectic geometry, especially in the presence of an obstruction bundle. The main motivation is to try to compare the symplectic and enumerative invariants of algebraic manifolds. These descriptions can also be used to enumerate rational curves with hig...
math
2,964
Hamiltonian structures on foliations
math.SG
We discuss hamiltonian structures of the Gelfand-Dorfman complex of projectable vector fields and differential forms on a foliated manifold. Such a structure defines a Poisson structure on the algebra of foliated functions, and embeds the given foliation into a larger, generalized foliation with presymplectic leaves. I...
math
2,965
The Hormander and Maslov Classes and Fomenko's Conjecture
math.SG
Some functorial properties are studied for the H\"{o}rmander classes defined for symplectic bundles. The behaviour of the Chern first form on a Lagrangian submanifold in an almost Hermitian manifold is also studied, and Fomenko's conjecture about the behaviour of a Maslov class on minimal Lagrangian submanifolds is con...
math
2,966
Vertical Cohomologies and Their Application to Completely Integrable Hamiltonian Systems
math.SG
Some functorial and topological properties of vertical cohomologies and their application to completely integrable Hamiltonian systems are studied.
math
2,967
Braids and symplectic four-manifolds with abelian fundamental group
math.SG
We explain how a version of Floer homology can be used as an invariant of symplectic manifolds with $b_1>0$. As a concrete example, we look at four-manifolds produced from braids by a surgery construction. The outcome shows that the invariant is nontrivial; however, it is an open question whether it is stronger than th...
math
2,968
On the Floer homology of plumbed three-manifolds
math.SG
We calculate the Heegaard Floer homologies for three-manifolds obtained by plumbings of spheres specified by certain graphs. Our class of graphs is sufficiently large to describe, for example, all Seifert fibered rational homology spheres. These calculations can be used to determine also these groups for other three-ma...
math
2,969
The residue formula and the Tolman-Weitsman theorem
math.SG
We give a simple direct proof (for the case of Hamiltonian circle actions with isolated fixed points) that Tolman and Weitsman's description of the kernel of the Kirwan map (in other words the sum of those equivariant cohomology classes vanishing on one side of a collection of hyperplanes) is equivalent to the characte...
math
2,970
Symplectic surfaces and generic J-holomorphic structures on 4-manifolds
math.SG
It is a well known fact that every embedded symplectic surface $\Sigma$ in a symplectic 4-manifold $(X^4,\omega)$ can be made $J$-holomorphic for some almost-complex structure $J$ compatible with $\omega$. In this paper we investigate when such a $J$ can be chosen from a generic set of almost-complex structures. As an ...
math
2,971
A Comparison of Hofer's Metrics on Hamiltonian Diffeomorphisms and Lagrangian Submanifolds
math.SG
We compare Hofer's geometries on two spaces associated with a closed symplectic manifold M. The first space is the group of Hamiltonian diffeomorphisms. The second space L consists of all Lagrangian submanifolds of $M \times M$ which are exact Lagrangian isotopic to the diagonal. We show that in the case of a closed sy...
math
2,972
A geometric proof of Conn's linearization theorem for analytic Poisson structures
math.SG
We give a geometric proof of Conn's linearization theorem for analytic Poisson structures, without using the fast convergence method.
math
2,973
A de Rham theorem for symplectic quotients
math.SG
We introduce a de Rham model for stratified spaces arising from symplectic reduction. It turns out that the reduced symplectic form and its powers give rise to well-defined cohomology classes, even on a singular symplectic quotient.
math
2,974
Examples for nonequivalence of symplectic capacities
math.SG
We construct an open bounded star-shaped set in R^4 whose cylindrical capacity is strictly bigger than its proper displacement energy.
math
2,975
Real loci of symplectic reductions
math.SG
Let $M$ be a compact, connected symplectic manifold with a Hamiltonian action of a compact $n$-dimensional torus $T$. Suppose that $M$ is equipped with an anti-symplectic involution $\sigma$ compatible with the $T$-action. The real locus of $M$ is the fixed point set $M^\sigma$ of $\sigma$. Duistermaat introduced real ...
math
2,976
Symplectic conifold transitions
math.SG
We introduce a symplectic surgery in six dimensions which collapses Lagrangian three-spheres and replaces them by symplectic two-spheres. Under mirror symmetry it corresponds to an operation on complex 3-folds studied by Clemens, Friedman and Tian. We describe several examples which show that there are either many more...
math
2,977
Toward a topological characterization of symplectic manifolds
math.SG
A topological condition is given, characterizing which closed manifolds in dimensions < 8 (and conjecturally in general) admit symplectic structures. The condition is the existence of a certain fibration-like structure called a hyperpencil. A deformation class of hyperpencils on a manifold X of any even dimension is sh...
math
2,978
Moduli of J-Holomorphic Curves with Lagrangian Boundary Conditions and Open Gromov-Witten Invariants for an $S^1$-Equivariant Pair
math.SG
Let $(X,\omega)$ be a symplectic manifold, $J$ be an $\omega$-tame almost complex structure, and $L$ be a Lagrangian submanifold. The stable compactification of the moduli space of parametrized $J$-holomorphic curves in $X$ with boundary in $L$ (with prescribed topological data) is compact and Hausdorff in Gromov's $C^...
math
2,979
On the Connectedness of Moduli Spaces of Flat Connections over Compact Surfaces
math.SG
We study the connectedness of the moduli space of gauge equivalence classes of flat G-connections on a compact orientable surface or a compact nonorientable surface for a class of compact connected Lie groups. This class includes all the compact, connected, simply connected Lie groups, and some non-semisimple classical...
math
2,980
Spectral invariants and length minimizing property of Hamiltonian paths
math.SG
In this paper we provide a criterion for the quasi-autonomous Hamiltonian path (``Hofer's geodesic'') on arbitrary closed symplectic manifolds $(M,\omega)$ to be length minimizing in its homotopy class in terms of the spectral invariants $\rho(G;1)$ that the author has recently constructed (math.SG/0206092). As an appl...
math
2,981
Cohomological Splitting of Coadjoint Orbits
math.SG
The rational cohomology of a coadjoint orbit ${\cal O}$ is expressed as tensor product of the cohomology of other coadjoint orbits ${\cal O}_k$, with $ \hbox{dim} {\cal O}_k< \hbox{dim} {\cal O}$.
math
2,982
Complexity one Hamiltonian SU(2) and SO(3) actions
math.SG
We consider compact connected six dimensional symplectic manifolds with Hamiltonian SU(2) or SO(3) actions with cyclic principal stabilizers. We classify such manifolds up to equivariant symplectomorphisms.
math
2,983
A remark on the c--splitting conjecture
math.SG
Let $M$ be a closed symplectic manifold and suppose $M\to P\to B$ is a Hamiltonian fibration. Lalonde and McDuff raised the question whether one always has $H^*(P;\mathbb Q)=H^*(M;\mathbb Q)\otimes H^*(B;\mathbb Q)$ as vector spaces. This is known as the c--splitting conjecture. They showed, that this indeed holds when...
math
2,984
Symplectic four-manifolds and conformal blocks
math.SG
We apply ideas from conformal field theory to study symplectic four-manifolds, by using modular functors to "linearise" Lefschetz fibrations. In Chern-Simons theory this leads to the study of parabolic vector bundles of conformal blocks. Motivated by the Hard Lefschetz theorem, we show the bundles of SU(2) conformal bl...
math
2,985
Distinguishing the Chambers of the Moment Polytope
math.SG
Let M be a compact manifold with a Hamiltonian T action and moment map Phi. The restriction map in equivariant cohomology from M to a level set Phi^{-1}(p) is a surjection, and we denote the kernel by I_p. When T has isolated fixed points, we show that I_p distinguishes the chambers of the moment polytope for M. In par...
math
2,986
Cup-length estimate for Lagrangian intersections
math.SG
In this paper we consider the Arnold conjecture on the Lagrangian intersections of some closed Lagrangian submanifold of a closed symplectic manifold with its image of a Hamiltonian diffeomorphism. We prove that if the Hofer's symplectic energy of the Hamiltonian diffeomorphism is less than a topology number defined by...
math
2,987
On Generalized Moment Maps for Symplectic Compact Group Actions
math.SG
A generalized moment map is proposed for arbitrary symplectic actions of compact connected Lie groups on closed symplectic manifolds, in the spirit of the circle -valued maps introduced by D. McDuff in the case of non-Hamiltonian circle actions. We study equivariance properties of generalized moments, show that they al...
math
2,988
On the holomorphicity of genus two Lefschetz fibrations
math.SG
We prove that any genus-2 Lefschetz fibration without reducible fibers and with ``transitive monodromy'' is holomorphic. The latter condition comprises all cases where the number of singular fibers is not congruent to 0 modulo 40. An auxiliary statement of independent interest is the holomorphicity of symplectic surfac...
math
2,989
On the Homotopy of Symplectomorphism Groups of Homogeneous Spaces
math.SG
Let ${\cal O}$ be a quantizable coadjoint orbit of a semisimple Lie group $G$. Under certain hypotheses we prove that $#(\pi_1(\text{Ham}({\cal O})))\geq #(Z(G))$, where $\text{Ham}({\cal O})$ is the group of Hamiltonian symplectomorphisms of ${\cal O}$.
math
2,990
Almost Homogeneous Poisson Spaces
math.SG
We prove that any holomorphic Poisson manifold has an open symplectic leaf which is a pseudo-K\"ahler submanifold, and we define an obstruction to study the equivariance of momentum map for tangential Poisson action. Some properties of almost homogeneous Poisson manifolds are studied and we show that any compact symple...
math
2,991
GKM theory for torus actions with non-isolated fixed points
math.SG
Let $M^{2d}$ be a compact symplectic manifold and $T$ a compact $n$-dimensional torus. A Hamiltonian action, $\tau$, of $T$ on $M$ is a GKM action if, for every $p \in M^T$, the isotropy representation of $T$ on $T_pM$ has pair-wise linearly independent weights. For such an action the projection of the set of zero and ...
math
2,992
Contact 3-manifolds with infinitely many Stein fillings
math.SG
Infinitely many contact 3-manifolds each admitting infinitely many, pairwise non-diffeomorphic Stein fillings are constructed. We use Lefschetz fibrations in our constructions and compute their first homologies to distinguish the fillings.
math
2,993
Non-contractible periodic orbits, Gromov invariants, and Floer-theoretic torsions
math.SG
In a previous paper, the author introduced a Floer-theoretic torsion invariant I_F, which roughly takes the form of a product of a power series counting perturbed pseudo-holomorphic tori, and the Reidemeister torsion of the symplectic Floer complex. We pointed out the formal resemblance of I_F with a generating functio...
math
2,994
Large Radius Limit and SYZ Fibrations of Hyper-Kahler Manifolds
math.SG
In this paper the relations between the existence of Lagrangian fibration of Hyper-K\"{a}hler manifolds and the existence of the Large Radius Limit is established. It is proved that if the the rank of the second homology group of a Hyper-K\"{a}hler manifold N of complex dimension $2n\geq4$ is at least 5, then there exi...
math
2,995
Lectures on four-dimensional Dehn twists
math.SG
These are notes from the 2003 C.I.M.E. summer school "symplectic 4-manifolds and algebraic surfaces". They cover the same material as the author's (by now ancient) Ph.D. thesis.
math
2,996
Noncentral extensions as anomalies in classical dynamical systems
math.SG
A two cocycle is associated to any action of a Lie group on a symplectic manifold. This allows to enlarge the concept of anomaly in classical dynamical systems considered by F. Toppan [in J. Nonlinear Math. Phys. 8, no.3 (2001) 518-533] so as to encompass some extensions of Lie algebras related to noncanonical actions.
math
2,997
Proofs On Arnold Chord Conjecture And Weinstein Conjecture In M\times C
math.SG
We give new proofs on Arnold Chord Conjecture and Weinstein Conjecture in M\times C which generalizes the previous works.
math
2,998
A Proof On Weinstein Conjecture On Cotangent Bundles Of Open Manifold
math.SG
We give an proof on the Weinstein conjecture on the cotangent bundles of open manifolds. Its proof is based on Gromov's nonlinear Fredholm alternative.
math
2,999
A Proof On Arnold Chord Conjecture In Cotangent Bundles
math.SG
We prove the Arnold chord conjecture on cotangent bundles of open manifold by Gromov's nonlinear Fredholm alternative for $J-$holomorphic curves.
math