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We give a generalization of the concept of near-symplectic structures to 2n dimensions. According to our definition, a closed 2-form \omega on a 2n-manifold M is near-symplectic, if it is symplectic outside a submanifold Z of codimension 3,…

Symplectic Geometry · Mathematics 2016-09-23 Ramón Vera

Several results in recent years have shown that the usual generalizations of taut foliations to higher dimensions, based only on topological concepts, lead to a theory that lacks the complexity of its 3-dimensional counterpart. Instead, we…

Symplectic Geometry · Mathematics 2025-01-08 Fabio Gironella , Klaus Niederkrüger , Lauran Toussaint

Log-symplectic structures are Poisson structures $\pi$ on $X^{2n}$ for which $\bigwedge^n \pi$ vanishes transversally. By viewing them as symplectic forms in a Lie algebroid, the $b$-tangent bundle, we use symplectic techniques to obtain…

Symplectic Geometry · Mathematics 2023-05-26 Gil R. Cavalcanti , Ralph L. Klaasse

Let $ \Phi: ({\mathbb C}^2, 0) \to ( {\mathbb C}^3, 0) $ be a finitely determined complex analytic germ and let $(\{f=0\},0)$ be the reduced equation of its image, a non-isolated hypersurface singularity. We provide the plumbing graph of…

Algebraic Geometry · Mathematics 2019-02-05 András Némethi , Gergő Pintér

The integral variation map and algebraic monodromy of isolated plane curve singularities are important homological invariants of the singularity which are still far from being completely understood. This work provides effective ways of…

Algebraic Geometry · Mathematics 2025-12-08 Pablo Portilla Cuadrado , Baldur Sigurðsson

We use topology of configuration spaces to give a characterization of Neuwirth--Stallings pairs $(S^5, K)$ with $\dim K = 2$. As a consequence, we construct polynomial map germs $(\mathbb{R}^{6},0)\to (\mathbb{R}^{3},0)$ with an isolated…

Geometric Topology · Mathematics 2016-05-06 R. Araújo Dos Santos , M. A. B. Hohlenwerger , O. Saeki , T. O. Souza

We study the vanishing cycles of a one-parameter smoothing of a complex analytic space and show that the weight filtration on its perverse cohomology sheaf of the highest degree is quite close to the monodromy filtration so that its graded…

Algebraic Geometry · Mathematics 2010-08-11 Alexandru Dimca , Morihiko Saito

For any plane curve singularity defined by an analytic function germ $f$, we construct a spine on each Milnor fiber simultaneously, that realizes the vanishing topology. In order to do so, we study the separatrices at the origin of the…

Algebraic Geometry · Mathematics 2025-12-05 Pablo Portilla Cuadrado , Baldur Sigurðsson

Using iterated vanishing cycles and convolution, we prove a motivic version of a conjecture of Steenbrink concerning the spectrum of hypersurface singularities

Algebraic Geometry · Mathematics 2007-12-05 G. Guibert , F. Loeser , M. Merle

We present a method to construct a symplecticity preserving renormalization group map of a chain of weakly nonlinear symplectic maps and obtain a general reduced symplectic map describing its long-time behaviour. It is found that the…

Chaotic Dynamics · Physics 2016-09-08 Shin-itiro Goto , Kazuhiro Nozaki , Hiroyasu Yamada

We produce examples of complex algebraic surfaces with isolated singularities such that these singularities are not metrically conic, i.e. the germs of the surfaces near singular points are not bi-Lipschitz equivalent, with respect to the…

Algebraic Geometry · Mathematics 2007-05-23 Lev Birbrair , Alexandre Fernandes

We introduce spectral Hirzebruch-Milnor classes for singular hypersurfaces. These can be identified with Steenbrink spectra in the isolated singularity case, and may be viewed as their global analogues in general. Their definition uses…

Algebraic Geometry · Mathematics 2017-03-23 Laurentiu Maxim , Morihiko Saito , Joerg Schuermann

We construct a local characteristic map to a symplectic manifold M via certain cohomology groups of Hamiltonian vector fields. For each p in M, the Leibniz cohomology of the Hamiltonian vector fields on R^{2n} maps to the Leibniz cohomology…

Symplectic Geometry · Mathematics 2011-11-10 Jerry Lodder

The Milnor fibre of any isolated hypersurface singularity contains many exact Lagrangian spheres: the vanishing cycles associated to a Morsification of the singularity. Moreover, for simple singularities, it is known that the only possible…

Symplectic Geometry · Mathematics 2015-10-16 Ailsa Keating

We use symplectic cohomology to study the non-uniqueness of symplectic structures on the smooth manifolds underlying affine varieties. Starting with a Lefschetz fibration on such a variety and a finite set of primes, the main new tool is a…

Symplectic Geometry · Mathematics 2010-08-04 Mohammed Abouzaid , Paul Seidel

We produce simply connected, minimal, symplectic Lefschetz fibrations realizing all the lattice points in the symplectic geography plane below the Noether line. This provides a symplectic extension of the classical works populating the…

Geometric Topology · Mathematics 2022-01-28 R. Inanc Baykur , Mustafa Korkmaz , Jonathan Simone

We prove that for any germ of complex analytic set in $\CC^n$ there exists a hypersurface singularity whose Milnor fibration has trivial geometric monodromy and fibre homotopic to the complement of the germ of complex analytic set. As an…

Algebraic Geometry · Mathematics 2011-02-17 Javier Fernandez de Bobadilla

Let f be a hypersurface surface local singularity whose zero set has 1-dimensional singular locus. We develop an explicit procedure that provides the boundary of the Milnor fibre of f as an oriented plumbed 3-manifold. The method provides…

Algebraic Geometry · Mathematics 2011-06-23 Andras Nemethi , Agnes Szilard

We study the monodromy diffeomorphism of Milnor fibrations of isolated complex surface singularities, by computing the family Seiberg--Witten invariant of Seifert-fibered Dehn twists using recent advances in monopole Floer homology. More…

Geometric Topology · Mathematics 2024-09-19 Hokuto Konno , Jianfeng Lin , Anubhav Mukherjee , Juan Muñoz-Echániz

For plane curve singularities we construct a mixed Hodge structure (MHS) over the integers on the fundamental group of the Milnor fiber. The concept nearby fundamental group is introduced and we develop a theory of iterated integrals along…

Algebraic Geometry · Mathematics 2007-05-23 Rainer H. Kaenders