Seminari de Geometria Algebraica UB-UPC-UAB
Anastasia Matveeva (HSE, Moscou, Rússia)
Generalized Riemann-Hilbert problem on an elliptic curve in dimensions 1 and 2
http://www.ub.edu/sga/
Divendres 18 de maig, 15 h, Aula T2, FMI-UB

Tobias Colding, born in Copenhagen, received his Ph.D. in 1992 at the University of Pennsylvania under Chris Croke. Since 2005 Colding has been a professor of Mathematics at MIT. He was on the faculty at the Courant Institute of New York University in various positions from 1992 to 2008.

In the early stage of his career, Colding did impressive work on manifolds with bounds on Ricci curvature. In 1998, he gave an invited address to the ICM in Berlin. He began coauthoring with William P. Minicozzi at this time: first on harmonic functions and later on minimal surfaces. In 2010 Tobias H. Colding received the Oswald Veblen Prize in Geometry together with William Minicozzi II for their profound work on minimal surfaces.

Since 2008 he has been a Fellow of the American Academy of Arts and Sciences, and since 2006 a foreign member of the Royal Danish Academy of Sciences and Letters, and also since 2006 an honorary professor of University of Copenhagen, Denmark.

 Més informació a: https://fme.upc.edu/ca/recerca/col-loqui-fme-upc/Conferencia%20Tobias%20Colding

Seminari de Geometria Algebraica UB-UPC-UAB
Guillem Blanco (Universitat de Politècnica de Catalunya)
Poles of the complex zeta function of a plane curve
http://www.ub.edu/sga/
Divendres 11 de maig, 15h, Aula T2, FMI-UB

Seminari de Geometria Algebraica UB-UPC-UAB
Eva Miranda (Universitat Politècnica de Catalunya)
Desingularizing singular symplectic structures
http://www.ub.edu/sga/
Divendres 4 de maig, 15h, Aula T2, FMI-UB

El seminari es posposa.

Seminari de Geometria Algebraica UB-UPC-UAB
Roser Homs Pons (Universitat de Barcelona)
Computing Gorenstein colength of Artin rings
http://www.ub.edu/sga/
Divendres 27 d'abril, 15h, Aula T2, FMI-UB

We present a new improvement in the linear programming technique to derive lower bounds on the information ratio of secret sharing schemes. We obtain non-Shannon-type bounds without using information inequalities explicitly. Our new technique makes it possible to determine the optimal information ratio of linear secret sharing schemes for all access structures on 5 participants and all graph-based access structures on 6 participants. In addition, new lower bounds are presented also for some small matroid ports and, in particular, the optimal information ratios of the linear secret sharing schemes for the ports of the Vamos matroid are determined.

This is a joint work with Oriol Farràs, Tarik Kaced, and Sebastià Martín.

Seminari de Geometria Algebraica UB-UPC-UAB
Enrico Sbarra (Università degli Studi di Pisa)
Jet schemes and determinantal varieties
http://www.ub.edu/sga/
Divendres 13 d’abril, 15h, Aula T2, FMI-UB