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Related papers: On the Milnor formula in arbitrary characteristic

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Given an algebroid plane curve $f=0$ over an algebraically closed field of characteristic $p\geq 0$ we consider the Milnor number $\mu(f)$, the delta invariant $\delta(f)$ and the number $r(f)$ of its irreducible components. Put $\bar…

Algebraic Geometry · Mathematics 2022-08-01 Evelia R. García Barroso , Arkadiusz Płoski

We study classical invariants for plane curve singularities $f\in K[[x,y]]$, $K$ an algebraically closed field of characteristic $p\geq 0$: Milnor number, delta invariant, kappa invariant and multiplicity. It is known, in characteristic…

Algebraic Geometry · Mathematics 2016-04-04 Hong Duc Nguyen

We study singularities f in K[[x_1,...,x_n]] over an algebraically closed field K of arbitrary characteristic with respect to right respectively contact equivalence, and we establish that the finiteness of the Milnor respectively the…

Algebraic Geometry · Mathematics 2012-03-27 Yousra Boubakri , Gert-Martin Greuel , Thomas Markwig

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

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

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

The Milnor number of an isolated hypersurface singularity, defined as the codimension $\mu(f)$ of the ideal generated by the partial derivatives of a power series $f$ whose zeros represent locally the hypersurface, is an important…

Algebraic Geometry · Mathematics 2023-08-15 Abramo Hefez , João Helder Olmedo Rodrigues , Rodrigo Salomão

We consider different notions of non-degeneracy, as introduced by Kouchnirenko (NND), Wall (INND) and Beelen-Pellikaan (WNND) for plane curve singularities $\{f(x,y) = 0\}$ and introduce the new notion of weighted homogeneous Newton…

Algebraic Geometry · Mathematics 2012-08-15 Gert-Martin Greuel , Nguyen Hong Duc

\noindent Let $\mu(f)$ resp. $c(f)$ be the Milnor number resp. the degree of the conductor of an irreducible power series $f\in \bK[[x,y]]$, where $\bK$ is an algebraically closed field of characteristic $p\geq 0$. It is well-known that…

Algebraic Geometry · Mathematics 2019-10-02 Evelia R. García Barroso , Arkadiusz Płoski

The Milnor number of an isolated hypersurface singularity, defined as the codimension $\mu(f)$ of the ideal generated by the partial derivatives of a power series $f$ that represents locally the hypersurface, is an important topological…

Algebraic Geometry · Mathematics 2023-07-25 Abramo Hefez , João Helder Olmedo Rodrigues , Rodrigo Salomão

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

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

Our recent extension of Arnold's classification includes all singularities of corank up to two equivalent to a germ with a non-degenerate Newton boundary, thus broadening the classification's scope significantly by a class which is…

Algebraic Geometry · Mathematics 2024-02-08 Janko Boehm , Magdaleen S. Marais , Gerhard Pfister

We investigate properties of the contact exponent (in the sense of Hironaka [Hi]) of plane algebroid curve singularities over algebraically closed fields of arbitrary characteristic. We prove that the contact exponent is an equisingularity…

Algebraic Geometry · Mathematics 2022-07-28 Evelia R. García Barroso , Arkadiusz Płoski

We discuss a problem of Arnold, whether every function is stably equivalent to one which is non-degenerate for its Newton diagram. We argue that the answer is negative. We describe a method to make functions non-degenerate after…

Algebraic Geometry · Mathematics 2020-12-25 Jan Stevens

In his groundbreaking work on classification of singularities with regard to right and stable equivalence of germs, Arnold has listed normal forms for all isolated hypersurface singularities over the complex numbers with either modality…

Algebraic Geometry · Mathematics 2020-10-21 Janko Boehm , Magdaleen S. Marais , Gerhard Pfister

If the first Betti number of the Milnor fibre of a plane curve singularity is zero, then the defining function is equivalent to $x^r$.

Algebraic Geometry · Mathematics 2018-01-12 Dirk Siersma

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

Let $f : X\to \Delta$ be a $1$-parameter family of $2$-dimensional isolated hypersurface singularities. In this paper, we show that if the Milnor number is constant, then any semistable model, obtained from $f$ after a sufficiently large…

Algebraic Geometry · Mathematics 2023-12-05 Marta Aldasoro Rosales

Let $f\colon X\to\mathbb{A}^1_k$ be a morphism from a smooth variety to an affine line with an isolated singular point. For such a singularity, we have two invariants. One is a non-degenerate symmetric bilinear form (de Rham), and the other…

Algebraic Geometry · Mathematics 2026-04-06 Daichi Takeuchi
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