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A Note on the Rational Cuspidal Curves

Piotr Nayar, Barbara Pilat (2014)

Bulletin of the Polish Academy of Sciences. Mathematics

In this short note we give an elementary combinatorial argument, showing that the conjecture of J. Fernández de Bobadilla, I. Luengo-Velasco, A. Melle-Hernández and A. Némethi [Proc. London Math. Soc. 92 (2006), 99-138, Conjecture 1] follows from Theorem 5.4 of Brodzik and Livingston [arXiv:1304.1062] in the case of rational cuspidal curves with two critical points.

Arithmetically Gorenstein curves on arithmetically Cohen-Macaulay surfaces.

Alberto Dolcetti (2002)

Collectanea Mathematica

Let Sigma C PN be a smooth connected arithmetically Cohen-Macaulay surface. Then there are at most finitely many complete linear systems on Sigma, not of the type |kH - K| (H hyperplane section and K canonical divisor on Sigma), containing arithmetically Gorenstein curves.

Biliaisons élémentaires en codimension 2

Mireille Martin-Deschamps (2006)

Annales de la faculté des sciences de Toulouse Mathématiques

Un théorème de Strano montre que si une courbe gauche localement Cohen-Macaulay n’est pas minimale dans sa classe de biliaison, elle admet une biliaison élémentaire strictement décroissante. R. Hartshorne a récemment donné une nouvelle preuve de ce résultat en le plaçant dans un contexte plus général. Dans cet article on apporte une précision, en utilisant les techniques introduites par Hartshorne : on montre que si un sous-schéma de codimension 2 localement Cohen-Macaulay de N n’est pas minimal...

Bornes pour la régularité de Castelnuovo-Mumford des schémas non lisses

Amadou Lamine Fall (2009)

Annales de l’institut Fourier

Nous montrons dans cet article des bornes pour la régularité de Castelnuovo-Mumford d’un schéma admettant des singularités, en fonction des degrés des équations définissant le schéma, de sa dimension et de la dimension de son lieu singulier. Dans le cas où les singularités sont isolées, nous améliorons la borne fournie par Chardin et Ulrich et dans le cas général, nous établissons une borne doublement exponentielle en la dimension du lieu singulier.

Braid Monodromy of Algebraic Curves

José Ignacio Cogolludo-Agustín (2011)

Annales mathématiques Blaise Pascal

These are the notes from a one-week course on Braid Monodromy of Algebraic Curves given at the Université de Pau et des Pays de l’Adour during the Première Ecole Franco-Espagnole: Groupes de tresses et topologie en petite dimension in October 2009.This is intended to be an introductory survey through which we hope we can briefly outline the power of the concept monodromy as a common area for group theory, algebraic geometry, and topology of projective curves.The main classical results are stated...

Braids in Pau – An Introduction

Enrique Artal Bartolo, Vincent Florens (2011)

Annales mathématiques Blaise Pascal

In this work, we describe the historic links between the study of 3 -dimensional manifolds (specially knot theory) and the study of the topology of complex plane curves with a particular attention to the role of braid groups and Alexander-like invariants (torsions, different instances of Alexander polynomials). We finish with detailed computations in an example.

Codimension 3 Arithmetically Gorenstein Subschemes of projective N -space

Robin Hartshorne, Irene Sabadini, Enrico Schlesinger (2008)

Annales de l’institut Fourier

We study the lowest dimensional open case of the question whether every arithmetically Cohen–Macaulay subscheme of N is glicci, that is, whether every zero-scheme in 3 is glicci. We show that a general set of n 56 points in 3 admits no strictly descending Gorenstein liaison or biliaison. In order to prove this theorem, we establish a number of important results about arithmetically Gorenstein zero-schemes in 3 .

Computing limit linear series with infinitesimal methods

Laurent Evain (2007)

Annales de l’institut Fourier

Alexander and Hirschowitz determined the Hilbert function of a generic union of fat points in a projective space when the number of fat points is much bigger than the greatest multiplicity of the fat points. Their method is based on a lemma which determines the limit of a linear system depending on fat points approaching a divisor.Other Hilbert functions were computed previously by Nagata. In connection with his counter-example to Hilbert’s fourteenth problem, Nagata determined the Hilbert function...

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