Paris Diderot Sorbonne Université CNRS

Groupes, Représentations et Géométrie

Chevalley’s Theorem on constructible images made constructive

Mohamed Barakat - Universität Siegen

vendredi 17 mai 2019 à 14:00
Sophie Germain en salle 1016 à 14 h 00

8 place Aurélie Nemours, 75013 Paris

Chevalley proved that the image of an algebraic morphism between algebraic varieties is a constructible set. Examples are orbits of algebraic group actions. A constructible set in a topological space is a finite union of locally closed sets and a locally closed set is the difference of two closed subsets. Simple examples show that even if the source and target of the morphism are affine varieties the image may neither be affine nor quasi-affine. In this talk I will present an Gröbner-basis-based algorithm which computes the constructible image of a morphism of affine spaces, along with applications from several fields.

Autres séances