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Related papers: A note on a question of Dimca and Greuel

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In this paper we give a complete answer to a question posed by Dimca and Greuel about the quotient of the Milnor and Tjurina numbers of a plane curve singularity. We put this question into a general framework of the study of the difference…

Algebraic Geometry · Mathematics 2021-09-13 Patricio Almirón

In this survey we overview the different approaches and solutions of a question posed by Dimca and Greuel about the quotient of the Milnor and Tjurina numbers.

Algebraic Geometry · Mathematics 2020-06-03 Patricio Almirón

In this paper we give a positive answer to a question of Dimca and Greuel about the quotient between the Milnor and the Tjurina numbers for any irreducible germ of plane curve singularity. This result is based on a closed formula for the…

Algebraic Geometry · Mathematics 2020-01-08 Maria Alberich-Carramiñana , Patricio Almirón , Guillem Blanco , Alejandro Melle-Hernández

We introduce the concept of good Saito's basis for a plane curve $S$ and we explore it to obtain a formula for the minimal Tjurina number in a topological class. In particular, we present a positive answer for a question of Dimca and Greuel…

Algebraic Geometry · Mathematics 2019-04-26 Marcelo E. Hernandes , Yohann Genzmer

We show the possible Milnor numbers of deformations of semi-quasi-homogeneous isolated plane curve singularities. In Theorem 1.1 we list integers can be attained as Milnor numbers of a given semi-quasi-homogeneous singularity.

Algebraic Geometry · Mathematics 2016-08-15 Maria Michalska , Justyna Walewska

In this paper, we use Hilbert-Samuel multiplicity, Hilbert-Kunz multiplicity, and s-multiplicity to establish a sharp upper bound for the quotient of the generalized Milnor numbers and the Tjurina numbers for isolated hypersurface…

Algebraic Geometry · Mathematics 2026-04-21 Hongrui Ma , Huaiqing Zuo

We introduce a notion of a homological index of a holomorphic 1-form on a germ of a complex analytic variety with an isolated singularity, inspired by X. G\'omez-Mont and G.-M. Greuel. For isolated complete intersection singularities it…

Algebraic Geometry · Mathematics 2007-05-23 W. Ebeling , S. M. Gusein-Zade , J. Seade

We collect some classical results about holomorphic 1-forms of a reduced complex curve singularity. They are used to study the pull-back of holomorphic 1-forms on an isolated complete intersection curve singularity under the normalization…

Algebraic Geometry · Mathematics 2019-09-17 Alexandru Dimca , Gert-Martin Greuel

In this note we provide a formula for the Tjurina number of a join of isolated hypersurface singularities in separated variables. From this we are able to provide a characterization of isolated hypersurface singularities whose difference…

Algebraic Geometry · Mathematics 2022-05-26 Patricio Almirón

The aim of this paper is to show the possible Milnor numbers of deformations of semi-quasi-homogeneous isolated plane curve singularities. Main result states that if $f$ is irreducible and nondegenerate, by deforming $f$ one can attain all…

Algebraic Geometry · Mathematics 2014-09-24 Maria Michalska , Justyna Walewska

We collect some classical results about holomorphic 1-forms of a reduced complex curve singularity, in particular of a complete intersection, and use them to compare the Milnor number, the Tjurina number and the dimension of the torsion…

Algebraic Geometry · Mathematics 2017-09-12 Gert-Martin Greuel

For an isolated hypersurface singularity $f=0$, the Milnor number $\mu$ is greater than or equal to the Tjurina number $\tau$ (the dimension of the base of the semi-universal deformation), with equality if $f$ is quasi-homogeneous. K. Saito…

Algebraic Geometry · Mathematics 2016-03-28 Jonathan Wahl

In this paper we establish a relationship between the Milnor number, the $\chi$-number, and the Tjurina number of a foliation with respect to an effective balanced divisor of separatrices. Moreover, using the G\'omez-Mont--Seade--Verjovsky…

Complex Variables · Mathematics 2025-12-29 Arturo Fernández-Pérez , Evelia R. García Barroso , Nancy Saravia-Molina

This paper gives an explicit formula for the Ehrhart quasi-polynomial of certain 2-dimensional polyhedra in terms of invariants of surface quotient singularities. Also, a formula for the dimension of the space of quasi-homogeneous…

Algebraic Geometry · Mathematics 2016-09-07 J. I. Cogolludo-Agustin , J. Martin-Morales , J. Ortigas-Galindo

J. Piontkowski described the homology of the Jacobi factor of a plane curve singularity with one Puiseux pair. We discuss the combinatorial structure of his answer, in particular, relate it to the bigraded deformation of Catalan numbers…

Algebraic Geometry · Mathematics 2012-07-26 E. Gorsky , Mikhail Mazin

In this paper we provide a family of reduced plane curves with two branches that have a constant Tjurina number in their equisingularity class, along with a closed formula for it in terms of topological data.

Algebraic Geometry · Mathematics 2025-01-23 Patricio Almirón , Marcelo E. Hernandes

We compute the Poincar\'e polynomials of the compactified Jacobians for plane curve singularities with Puiseaux exponents $(nd,md,md+1)$, and relate them to the combinatorics of $q,t$-Catalan numbers in the non-coprime case. We also confirm…

Algebraic Geometry · Mathematics 2024-06-21 Eugene Gorsky , Mikhail Mazin , Alexei Oblomkov

Piontkowski proved the existence of affine cell decompositions of Jacobian factors of plane curve singularities with a single Puiseux pair. He also provided a combinatorial description of the Euler numbers and Betti numbers of these…

Algebraic Geometry · Mathematics 2025-06-03 Masahiro Watari

A closed subscheme of codimension two $T \subset P^2$ is a quasi complete intersection (q.c.i.) of type $(a,b,c)$ if there exists a surjective morphism $\mathcal{O} (-a) \oplus \mathcal{O} (-b) \oplus \mathcal{O} (-c) \to \mathcal{I} _T$.…

Algebraic Geometry · Mathematics 2019-01-04 Philippe Ellia

This paper aims to prove that given a isolated complete intersection singularity, the Milnor number will be bounded by a bound depending only on Tjurina number and dimension of the singularity. The proof uses A$\mathfrak{m}$AC (introduced…

Algebraic Geometry · Mathematics 2023-05-31 A. J. Parameswaran , Mohit Upmanyu
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