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We study the relationship between the Milnor and Tjurina numbers of a singular foliation $\mathcal{F}$, in the complex plane, with respect to a balanced divisor of separatrices $\mathcal{B}$ for $\mathcal{F}$. For that, we associate with…

Complex Variables · Mathematics 2025-03-03 Arturo Fernández-Pérez , Evelia R. García Barroso , Nancy Saravia-Molina

In this paper, we introduce the notions of the $k$-th Milnor number and the $k$-th Tjurina number for a germ of holomorphic foliation on the complex plane with an isolated singularity at the origin. We develop a detailed study of these…

Complex Variables · Mathematics 2025-11-11 Marcela Ribeiro , Arturo Fernández-Pérez

We generalize Mattei's result relative to the Brian\c{c}on-Skoda theorem for foliations to the family of foliations of the second type. We use this generalization to establish relationships between the Milnor and Tjurina numbers of…

Complex Variables · Mathematics 2023-09-26 Arturo Fernández-Pérez , Evelia R. García Barroso , Nancy Saravia-Molina

We study numerical invariants associated with the reduction of singularities of holomorphic foliation germs on $(\mathbb{C}^2, 0)$. Building on our previous work on generalized curve foliations, we extend explicit formulas for several…

Algebraic Geometry · Mathematics 2026-04-10 Maycol Falla Luza , Percy Fernández Sánchez , David marin

In this paper, we revisit local invariants (G\'omez-Mont-Seade-Verjovsky, variation, Camacho-Sad and Baum-Bott indices) associated with singular holomorphic foliations on $(\mathbb{C}^2 , 0)$ and we provide semi-global formulas for them in…

Algebraic Geometry · Mathematics 2025-08-15 Maycol Falla Luza , Arturo Fernández-Pérez , David Marín , Rudy Rosas

This paper contributes to the solution of the Poincare problem, which is to bound the degree of a (generalized algebraic) leaf of a (singular algebraic) foliation of the complex projective plane. The first theorem gives a new sort of bound,…

Algebraic Geometry · Mathematics 2007-05-23 E. Esteves , S. Kleiman

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 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 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

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

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

We study functions on isolated singularities and prove some results of type Milnor number = Tjurina number. We use them to endow the base space of their miniversal deformation with the structure of F-manifold.

Algebraic Geometry · Mathematics 2007-05-23 Ignacio de Gregorio

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

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

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

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…

Given a positive singular hermitian metric of a pseudoeffective line bundle on a complex Kaehler manifold, a singular foliation is constructed satisfying certain analytic analogues of numerical conditions. This foliation refines Tsuji's…

Algebraic Geometry · Mathematics 2007-05-23 Thomas Eckl

We define the Milnor number -- as the intersection number of two holomorphic sections -- of a one-dimensional holomorphic foliation $\mathscr{F}$ with respect to a compact connected component $C$ of its singular set. Under certain…

Complex Variables · Mathematics 2023-02-10 Arturo Fernández-Pérez , Gilcione Nonato Costa , Rudy Rosas

Let $F$ be a one-dimensional holomorphic foliation on $\mathbb{P}^n$ such that $W\subset Sing(F)$, where $W$ is a smooth complete intersection variety. We determine and compute the variation of the Milnor number $ \mu(F, W)$ under blowups,…

Algebraic Geometry · Mathematics 2025-01-20 Maurício Corrêa , Gilcione Nonato Costa

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
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