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

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The Milnor formula $\mu=2\delta-r+1$ relates the Milnor number $\mu$, the double point number $\delta$ and the number $r$ of branches of a plane curve singularity. It holds over the fields of characteristic zero. Melle and Wall based on a…

Algebraic Geometry · Mathematics 2018-12-18 Evelia R. García Barroso , Arkadiusz Płoski

We study codimension two determinantal varieties with isolated singularities. These singularities admit a unique smoothing, thus we can define their Milnor number as the middle Betti number of their generic fiber. For surfaces in C^4, we…

Algebraic Geometry · Mathematics 2011-11-29 Miriam da Silva Pereira , Maria Aparecida Soares Ruas

There is an elegant relation found by Fabricius-Bjerre [Math. Scand 40 (1977) 20--24] among the double tangent lines, crossings, inflections points, and cusps of a singular curve in the plane. We give a new generalization to singular curves…

Geometric Topology · Mathematics 2009-06-30 Abigail Thompson

In this paper we extend the concept of Milnor fiber and Milnor number of a curve singularity allowing the ambient space to be a quotient surface singularity. A generalization of the local {\delta}-invariant is defined and described in terms…

Algebraic Geometry · Mathematics 2012-06-12 Jose Ignacio Cogolludo-Agustin , Jorge Martin-Morales , Jorge Ortigas-Galindo

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 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

In this paper we give some criteria for a family of generically reduced plane curve singularities to be equinormalizable. The first criterion is based on the $\delta$-invariant of a (non-reduced) curve singularity which is introduced by…

Algebraic Geometry · Mathematics 2011-03-18 Công-Trình Lê

We construct a class of noncommutative crepant resolutions of any Kleinian singularity in the form of noncommutative algebras over its crepant partial resolutions. We argue that such resolutions are Morita equivalent to the canonical…

Algebraic Geometry · Mathematics 2025-09-29 Lukas Bertsch

We discuss Weber's formula which gives the quotient of two Thetanullwerte for a plane smooth quartic in terms of the bitangents. In particular, we show how it can easily be derived from the Riemann-Jacobi formula.

Algebraic Geometry · Mathematics 2015-03-04 Enric Nart , Christophe Ritzenthaler

Reduced power series in two variables with coefficients in a field of characteristic zero satisfy a well-known formula that relates a codimension related to the normalization of a ring and the jacobian ideal. In the general case Deligne…

Algebraic Geometry · Mathematics 2025-04-07 Enrique Artal Bartolo , Pierrette Cassou-Noguès

The purpose of this note is to suggest an analogue for genus 2 curves of part of Gross and Zagier's work on elliptic curves. Experimentally, for genus 2 curves with CM by a quartic CM field K, it appears that primes dividing the…

Number Theory · Mathematics 2007-05-23 Kristin Lauter

Greuel, Lossen and Shustin gave a general sufficient numerical condition for the T-smoothness (smoothness and expected dimension) of equisingular families of plane curves. This condition involves a new invariant \gamma for plane curve…

Algebraic Geometry · Mathematics 2009-07-28 Thomas Keilen , Christoph Lossen

Let $f=0$ be a plane algebraic curve of degree $d>1$ with an isolated singular point at the origin of the complex plane. We show that the Milnor number $\mu_0(f)$ is less than or equal to $(d-1)^2-\left[\frac{d}{2}\right]$, unless $f=0$ is…

Algebraic Geometry · Mathematics 2013-05-23 Arkadiusz Płoski

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

The present paper addresses a semimodule counting conjecture of Moreno-Fr\'{i}as and Rosales for numerical semigroups. Applying Pfister and Steenbrink's Theory for punctual Hilbert schemes of curve singularities, we show that this…

Number Theory · Mathematics 2024-03-22 Masahiro Watari

In this note we study a problem of A'Campo about the minimal non-zero difference between the Milnor numbers of a germ of plane curve and one of its deformation.

Algebraic Geometry · Mathematics 2007-05-23 Arnaud Bodin

Let f_0 be a plane curve singularity. We study the Minor numbers of singularities in deformations of f_0. We completely describe the set of these Milnor numbers for homogeneous singularities f_0 in the case of non-degenerate deformations…

Algebraic Geometry · Mathematics 2016-11-17 Szymon Brzostowski , Tadeusz Krasinski , Justyna Walewska

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 study deformations of plane curve singularities from an analytic point of view and obtain some new concrete results. We show some rather unexpected properties of Puiseux coefficients treated as functions on a suitably defined parameter…

Algebraic Geometry · Mathematics 2012-03-20 Maciej Borodzik

We generalize two classical formulas for complete intersection curves by introducing the the complete intersection discrepancy of a curve as a correction term. The first is a well-known multiplicity formula in singularity theory, due to…

Algebraic Geometry · Mathematics 2026-04-07 Andrei Benguş-Lasnier , Antoni Rangachev