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Related papers: A Note on 1-Forms for Reduced Curve Singularities

200 papers

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

For a convenient and Newton non-degenerate singularity, the Milnor number is computed from the complement of its Newton diagram in the first quadrant, so-called Kouchnirenko's formula. In this paper, we consider tropical curves dual to…

Algebraic Geometry · Mathematics 2016-09-07 Takuhiro Takahashi

The paper suggests new topological lower bounds for the number of zeros of closed 1-forms within a given cohomology class. The main new technical tool is the deformation complex, which allows to pass to a singular limit and reduce the…

Differential Geometry · Mathematics 2007-05-23 Michael Farber

We study the pull-back of regular 1-forms on a complex irreducible plane curve singularity under the normalization morphism.

Algebraic Geometry · Mathematics 2017-09-07 Alexandru Dimca

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 present an intersection-theoretical approach to the invariants of plane curve singularities $\mu$, $\delta$, $r$ related by the Milnor formula $2\delta=\mu+r-1$. Using Newton transformations we give formulae for $\mu$, $\delta$, $r$…

Algebraic Geometry · Mathematics 2012-07-09 Pierrette Cassou-Noguès , Arkadiusz Płoski

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

An old conjecture of Durfee 1978 bounds the ratio of two basic invariants of complex isolated complete intersection surface singularities: the Milnor number and the singularity (or geometric) genus. We give a counterexample for the case of…

Algebraic Geometry · Mathematics 2011-11-08 Dmitry Kerner , András Némethi

In this paper we present an analogue of the Milnor number for one dimensional local ring, and we show that it satisfies analogous properties to those of the Milnor number of plane curves over a field. In addition, we present two analogues…

Commutative Algebra · Mathematics 2026-02-13 Yotam Svoray

Generic relative immersions of compact one-manifolds in the closed unit disk, i.e. divides, provide a powerful combinatorial framework, and allow a topological construction of fibered classical links, for which the monodromy diffeomorphism…

Geometric Topology · Mathematics 2025-03-14 Norbert A'Campo , Pablo Portilla Cuadrado

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 work we study algebraic, geometric and topological properties of the Milnor classes of local complete intersections with arbitrary singularities. We describe first the Milnor class of the intersection of a finite number of…

Algebraic Geometry · Mathematics 2012-08-28 R. Callejas-Bedregal , M. F. Z. Morgado , J. Seade

We review properties of closed meromorphic $1$-forms and of the foliations defined by them. We present and explain classical results from foliation theory, like index theorems, the existence of separatrices, and resolution of singularities…

Complex Variables · Mathematics 2023-06-07 Jorge Vitório Pereira

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

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

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 relate the Bruce-Roberts numbers of a 1-form with respect to an ICIS to other invariants as the GSV-index, Tjurina and Milnor numbers.

This paper generalizes existing methods to derive stronger bounds on the modality of hypersurface singularities. Our results demonstrate that each sudden jump in the extended Tjurina number necessarily increases the modality. Furthermore,…

Algebraic Geometry · Mathematics 2026-04-20 Hongrui Ma , Aoyu Ying , Huaiqing Zuo

Motivated by the work of Kontsevich-Soibelman on the comparison of isomorphisms conjecture for closed algebraic $1$-forms, we establish a Riemann-Hilbert correspondence of Deligne-Malgrange type. As an application, we prove a variant of the…

Algebraic Geometry · Mathematics 2026-04-21 Yota Shamoto

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