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We first present the construction of the moduli space of real pseudo-holomorphic curves in a given real symplectic manifold. Then, following the approach of Gromov and Witten, we construct invariants under deformation of real rational…

Algebraic Geometry · Mathematics 2007-05-23 Jean-Yves Welschinger

In this short note we give a characterization of smooth projective varieties of Picard number one that are separably uniruled but not separably rationally connected. We also give a sufficient condition involving the torsion order and the…

Algebraic Geometry · Mathematics 2019-07-17 Jason Michael Starr , Zhiyu Tian

We review and streamline our previous results and the results of Y.Ostrover on the existence of Calabi quasi-morphisms and symplectic quasi-states on symplectic manifolds with semi-simple quantum homology. As an illustration, we discuss the…

Symplectic Geometry · Mathematics 2007-12-18 Michael Entov , Leonid Polterovich

Let M be a connected, symplectic 4-manifold. A semitoric integrable system on M essentially consists of a pair of independent, real-valued, smooth functions J and H on the manifold M, for which J generates a Hamiltonian circle action under…

Symplectic Geometry · Mathematics 2009-03-20 Alvaro Pelayo , San Vu Ngoc

We study smooth, complex Fano 4-folds X with a rational contraction onto a 3-fold, namely a rational map X-->Y that factors as a sequence of flips X-->X' followed by a surjective morphism X'->Y with connected fibers, where Y is normal,…

Algebraic Geometry · Mathematics 2024-10-30 Cinzia Casagrande , Saverio Andrea Secci

We study smooth projective varieties with small dual variety using methods from symplectic topology. We prove the affine parts of such varieties are subcritical, and that the hyperplane class is invertible in their quantum cohomology. We…

Algebraic Geometry · Mathematics 2012-06-29 Paul Biran , Yochay Jerby

In the present paper, we obtain real-analytic symplectic normal forms for integrable Hamiltonian systems with $n$ degrees of freedom near singular points having the type ``universal unfolding of $A_n$ singularity'', $n\ge1$ (local…

Symplectic Geometry · Mathematics 2025-08-05 Elena A. Kudryavtseva

We show that simply connected contact manifolds that are subcritically Stein fillable have a unique symplectically aspherical filling up to diffeomorphism. Various extensions to manifolds with non-trivial fundamental group are discussed.…

Symplectic Geometry · Mathematics 2019-11-11 Kilian Barth , Hansjörg Geiges , Kai Zehmisch

We define, for smooth projective orbifold pairs $(X,D)$ notions of `slope Rational connectedness', and of orbifold `slope Rational quotient' . These notions extend to this larger context the classical notions of rationally connected…

Algebraic Geometry · Mathematics 2017-12-27 Frederic Campana

We provide a closed, simply connected, symplectic $6$-manifold having infinitely many codimension $2$ symplectic submanifolds. These are mutually homologous but homotopy inequivalent, and furthermore, they cannot admit complex structures.…

Symplectic Geometry · Mathematics 2025-06-17 Takahiro Oba

This paper is a contribution to piecewise linear (PL) symplectic topology. We define the notion of PL symplectic manifold as being a combinatorial manifold endowed with a piecewise constant Whitney symplectic form and investigate possible…

Differential Geometry · Mathematics 2024-06-27 Mélanie Bertelson , Julie Distexhe

We show that closed, connected 4-manifolds up to connected sum with copies of the complex projective plane are classified in terms of the fundamental group, the orientation character and an extension class involving the second homotopy…

Geometric Topology · Mathematics 2023-04-13 Daniel Kasprowski , Mark Powell , Peter Teichner

In this paper we show that every degree 2 homology class of a 2n-dimensional symplectic manifold is represented by an immersed symplectic surface if it has positive symplectic area. Moreover, the symplectic surface can be chosen to be…

Symplectic Geometry · Mathematics 2008-12-31 Tian-Jun Li

We consider rationally connected complex projective manifolds M and show that their loop spaces--infinite dimensional complex manifolds--have properties similar to those of M. Furthermore, we give a finite dimensional application concerning…

Algebraic Geometry · Mathematics 2007-05-23 L. Lempert , E. Szabo

O'Grady showed that certain special sextics in $\mathbb{P}^5$ called EPW sextics admit smooth double covers with a holomorphic symplectic structure. We propose another perspective on these symplectic manifolds, by showing that they can be…

Algebraic Geometry · Mathematics 2009-07-17 Atanas Iliev , Laurent Manivel

In this paper, we study the symplectic geometry of singular conifolds of the finite group quotient $$ W_r=\{(x,y,z,t)|xy-z^{2r}+t^2=0 \}/\mu_r(a,-a,1,0), r\geq 1, $$ which we call orbi-conifolds. The related orbifold symplectic conifold…

Symplectic Geometry · Mathematics 2008-04-22 Bohui Chen , An-Min Li , Qi Zhang , Guosong Zhao

Fintushel and Stern have proved that if S \subset X is a symplectic surface in a symplectic 4-manifold such that S has simply-connected complement and nonnegative self-intersection, then there are infinitely many topologically equivalent…

Geometric Topology · Mathematics 2008-04-18 Thomas E. Mark

We initiate here the study of Gromov-Witten theory of locally conformally symplectic manifolds or $\lcs$ manifolds, $\lcsm$'s for short, which are a natural generalization of both contact and symplectic manifolds. We find that the main new…

Symplectic Geometry · Mathematics 2021-02-12 Yasha Savelyev

In this paper we construct a family of symplectic 4--manifolds with positive signature for any given fundamental group $G$ that approaches the BMY line. The family is used to show that one cannot hope to do better than than the BMY…

Geometric Topology · Mathematics 2007-05-23 Scott Baldridge , Paul Kirk

We show that every indecomposable conical symplectic hypersurface of dimension four is isomorphic to the known one, namely, the Slodowy slice $X_n$ which is transversal to the nilpotent orbit of Jordan type $[2n-2, 1, 1]$ in the nilpotent…

Algebraic Geometry · Mathematics 2022-10-27 Ryo Yamagishi