Seminario de Álgebra Conmutativa, Geometría Algebraica y Aritmética

Jueves 26 de junio a las 12:00 en el aula 420 del módulo 17 (Departamento de Matemáticas UAM)

Conferenciante: David Bourqui (Université de Rennes)

Título: Degenerations of families of arcs and torus actions

Resumen: Formal arcs on an algebraic variety are naturally organized into families
according to the valuation they define through their contact
order along regular functions. The possible degenerations are encoded
by a poset structure on the set of divisorial valuations, called the
Nash order. I will describe an explicit "semi-combinatorial" interpretation
of the Nash order in the case of non-rational varieties equipped with a torus
action of complexity one, and its consequences on the Nash
problem. Time permitting, I will also say a few words about the issues
in the rational case. Joint work with K. Langlois and H. Mourtada.