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We give two examples of plane curve arrangements of pencil type which are very close to line arrangements, though the action of the monodromy operator on the first cohomology group of the Milnor Fiber has eigenvalues of order 5 and 6,…

Algebraic Geometry · Mathematics 2016-06-16 Pauline Bailet

Suppose that $f$ defines a singular, complex affine hypersurface. If the critical locus of $f$ is one-dimensional, we obtain new general bounds on the ranks of the homology groups of the Milnor fiber of $f$. This result has an interesting…

Algebraic Geometry · Mathematics 2007-05-23 Lê Dũng Tráng , David B. Massey

We introduce the notion of curvature parameters for singular plane curves with finite multiplicities and define the notion of curvatures for them. We then provide criteria to determine their singularity types for A-simple singularities. As…

Differential Geometry · Mathematics 2025-12-30 Toshizumi Fukui , Saiki Hoshino

While intersection cohomology is stable under small resolutions, both ordinary and intersection cohomology are unstable under smooth deformation of singularities. For complex projective algebraic hypersurfaces with an isolated singularity,…

Algebraic Topology · Mathematics 2016-05-24 Markus Banagl , Laurentiu Maxim

We study curve singularities in a smooth surface relative to a smooth boundary curve. We consider the semiuniversal deformations and equisingular deformations of curves with a fixed local intersection number $w$ with the boundary, and prove…

Algebraic Geometry · Mathematics 2025-10-20 Nobuyoshi Takahashi

We study the vanishing neighbourhood of non-isolated singularities of functions on singular spaces by associating a general linear function. We use the carrousel monodromy in order to show how to get a better control over the attaching of…

Complex Variables · Mathematics 2016-09-07 Mihai Tibar

We extend the notion of connection in order to be able to study singular geometric structures, namely, we consider a notion of connection on a Lie algebroid which is a natural extension of the usual concept of connection. Using connections,…

Differential Geometry · Mathematics 2007-05-23 Rui Loja Fernandes

An important result for regular foliations is their formal semi-local triviality near simply connected leaves. We extend this result to singular foliations for all 2-connected leaves and a wide class of 1- connected leaves by proving a…

Differential Geometry · Mathematics 2020-05-12 Camille Laurent-Gengoux , Leonid Ryvkin

We complete the computation of the integral homology of the generalized braid group $B$ associated to an arbitrary irreducible complex reflection group $W$ of exceptional type. In order to do this we explicitely computed the…

Group Theory · Mathematics 2016-05-24 Ivan Marin

We associate (under a minor assumption) to any analytic isolated singularity of dimension $n\geq 2$ the `analytic lattice cohomology' ${\mathbb H}^*_{an}=\oplus_{q\geq 0}{\mathbb H}^q_{an}$. Each ${\mathbb H}^q_{an}$ is a graded ${\mathbb…

Algebraic Geometry · Mathematics 2021-09-24 Tamás Ágoston , András Némethi

We investigate the cohomology of the Milnor fibre of a reflection arrangement as a module for the group $\Gamma$ generated by the reflections, together with the cyclic monodromy. Although we succeed completely only for unitary reflection…

Algebraic Geometry · Mathematics 2013-07-29 Alexandru Dimca , Gus Lehrer

In this note we consider the Milnor fiber $F$ associated to a reduced projective plane curve $C$. A computational approach for the determination of the characteristic polynomial of the monodromy action on the first cohomology group of $F$,…

Algebraic Geometry · Mathematics 2017-08-30 Alexandru Dimca , Gabriel Sticlaru

In arXiv:1911.08213 it was conjectured that the compactly supported cohomology of the $m$-th restricted contact locus of an isolated hypersurface singularity coincides, up to a shift, with the Floer cohomology of the $m$-th iterate of the…

Algebraic Geometry · Mathematics 2025-09-03 Javier de la Bodega , Eduardo de Lorenzo Poza

Kodaira's classification of singular fibers in elliptic fibrations and its translation into the language of monodromies and Lefschetz fibrations has been a boon to the study of 4-manifolds. In this article, we begin the work of translating…

Geometric Topology · Mathematics 2023-03-06 Sümeyra Sakallı , Jeremy Van Horn-Morris

We consider a linear $2\times2$ matrix ODE with two coalescing regular singularities. This coalescence is restricted with an isomonodromy condition with respect to the distance between the merging singularities in a way consistent with the…

Classical Analysis and ODEs · Mathematics 2009-11-11 A. V. Kitaev

This is the paper as published. The topology of a complex plane curve singularity with real branches is deduced from any real deformation having delta crossings. An example of the computation of the global geometric monodromy of a…

alg-geom · Mathematics 2007-05-23 Norbert A'Campo

Fixed a point O on a non-singular surface S and a complete mO-primary ideal I in its local ring, the curves on the surface X obtained by blowing-up I are studied in terms of the base points of I. Criteria for the principality of these…

Algebraic Geometry · Mathematics 2007-05-23 Jesus Fernandez-Sanchez

We prove fibration theorems \`a la Milnor for differentiable real maps with non isolated critical values. We study the situation for maps with linear discriminant, and prove that the concept of d-regularity is the key point for the…

Algebraic Geometry · Mathematics 2020-02-18 JosÉ Luis Cisneros-Molina , AurÉlio Menegon , JosÉ Seade , Jawad Snoussi

A theorem of Mumford states that, on complex surfaces, any normal isolated singularity whose link is diffeomorphic to a sphere is actually a smooth point. While this property fails in higher dimensions, McLean asks whether the contact…

Algebraic Geometry · Mathematics 2017-01-24 Tommaso de Fernex , Yu-Chao Tu

This paper is devoted to the analysis of linear second order discrete-time descriptor systems (or singular difference equations (SiDEs) with control). Following the algebraic approach proposed by Kunkel and Mehrmann for pencils of matrix…

Numerical Analysis · Mathematics 2020-05-13 Vu Hoang Linh , Ha Phi