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Related papers: On the Saito's basis and the Tjurina Number for Pl…

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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

In this work we study the \emph{Saito number} of a plane curve and we present a method to determine the minimal Saito number for plane curves in a given equisingularity class, that gives rise to an actual algorithm. In particular…

Algebraic Geometry · Mathematics 2024-06-21 Yohann Genzmer , Marcelo E. Hernandes

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 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 present some results concerning the Saito module and the torsion submodule of an analytic plane curve, and we provide a method for computing them. Using this algorithm, we compute analytic invariants for plane curves with multiplicity…

Algebraic Geometry · Mathematics 2025-05-27 Emilio de Carvalho , Percy Fernández-Sánchez , Marcelo Escudeiro Hernandes

We show that a general lower bound for the global Tjurina number of a reduced complex projective plane curve, given by A. A. du Plessis and C.T.C. Wall, can be improved when the curve is a line arrangement.

Algebraic Geometry · Mathematics 2019-01-17 Alexandru Dimca

In this note we give a positive answer to a question of Dimca and Greuel about the quotient between the Milnor and Tjurina numbers of an isolated plane curve singularity in the cases of one Puiseux pair and semi-quasi-homogeneous…

Algebraic Geometry · Mathematics 2019-03-13 Patricio Almirón , Guillem Blanco

In this paper we describe how to compute a Saito basis of a cusp, a plane curve with only one Puiseux pair. Moreover, the 1-forms of the Saito basis that we compute are characterized in terms of their divisorial orders associated to the…

Algebraic Geometry · Mathematics 2024-04-02 Felipe Cano , Nuria Corral , David Senovilla-Sanz

In this work, we refine a formula for the Tjurina number of a reducible algebroid plane curve defined over $\mathbb C$ obtained in the more general case of complete intersection curves in [1]. As a byproduct, we answer the affirmative to a…

Algebraic Geometry · Mathematics 2024-09-18 Abramo Hefez , Marcelo Escudeiro Hernandes

We describe the 0-th Fitting ideal of the Jacobian module of a plane curve in terms of determinants involving the Jacobian syzygies of this curve. This leads to new characterizations of maximal Tjurina curves, that is of non free plane…

Algebraic Geometry · Mathematics 2019-04-17 Alexandru Dimca , Gabriel Sticlaru

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

We give a formula relating the total Tjurina number and the generic splitting type of the bundle of logarithmic vector fields associated to a reduced plane curve. By using it, we give a characterization of nearly free curves in terms of…

Algebraic Geometry · Mathematics 2019-09-17 Takuro Abe , Alexandru Dimca

We prove that there exists a>0 such that for any integer d>2 and any topological types S_1,...,S_n of plane curve singularities, satisfying $\mu(S_1)+...+\mu(S_n) \leq ad^2$, there exists a reduced irreducible plane curve of degree d with…

alg-geom · Mathematics 2009-10-30 Gert-Martin Greuel , Christoph Lossen , Eugenii Shustin

In this paper we compute an explicit closed formula for the total Tjurina number $\tau(C)$ of a reduced projective plane curve $C$ in terms of the graded Betti numbers of the corresponding Jacobian algebra. This formula allows a completely…

Algebraic Geometry · Mathematics 2026-01-26 Alexandru Dimca , Gabriel Sticlaru

We give a characterization of nearly free plane curves in terms of their global Tjurina numbers, similar to the characterization of free curves as curves with a maximal Tjurina number, due to A. A. du Plessis and C.T.C. Wall. It is also…

Algebraic Geometry · Mathematics 2017-08-30 Alexandru Dimca

We study the Jacobian scheme of a plane algebraic curve at an ordinary singularity, characterizing it through a geometric property. We compute the Tjurina number for a family of curves at an ordinary singularity showing that it reaches the…

Algebraic Geometry · Mathematics 2024-02-08 Stefano Canino , Alessandro Gimigliano , Monica Idà

Differently from the Milnor number, no formula relating the Tjurina number of a reducible algebroid curve to invariants of its branches was known. The aim of this work is to provide such a formula for a complete intersection algebroid curve…

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

First we give a sharp upper bound for the cardinal $m$ of a minimal set of generators for the module of Jacobian syzygies of a complex projective reduced plane curve $C$. Next we discuss the sharpness of an upper bound, given by A. du…

Algebraic Geometry · Mathematics 2019-04-30 Alexandru Dimca , Gabriel Sticlaru

We investigate combinatorial bounds for the total Tjurina numbers of plane curve arrangements. Focusing on arrangements of lines and conics in $\mathbb{P}^2$ that admit only ordinary quasi-homogeneous singularities, we derive new structural…

Algebraic Geometry · Mathematics 2026-02-27 Piotr Pokora
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