Schedule:
14:30-15:30 Karin Schaller (FU Berlin): NObodies are perfect, semigroups are not
15:30-16:00 Break
16:00-17:00 Lukas Kühne (Universität Bielefeld): The realization space of a matroid
Karin Schaller: NObodies are perfect, semigroups are not
Abstract: NObodies are asymptotic limits of certain valuation
semigroups. Their construction depends on a given flag of subvarieties.
We investigate toric surfaces together with non-toric flags and
determine when the associated valuation semigroups are finitely
generated. This is a joint work with K. Altmann, C. Haase, A. Küronya,
and L. Walter.
Abstract: A matroid is a fundamental and widely studied object in combinatorics. Following a brief introduction to matroids, I will showcase parts of a new OSCAR module for matroids using several examples. My emphasis will be on the computation of the realization space of a matroid, which is the space of all hyperplane arrangements that have the given matroid as their intersection lattice.
In the second part, I will discuss an application in the realm of algebraic geometry, namely a novel connection between matroid realization spaces and the elliptic modular surfaces.
______________________________________________________________________________________________________________
The talks will be given in a hybrid format. If you are close-by, please join us in Frankfurt in room 711 (groß), Robert-Mayer-Str. 10, for two in-person talks. Otherwise, we're hoping to see you on Zoom. The Zoom info will be sent out to the mailing list as usual.
Schedule:
14:30-15:30 Andreas Bernig (Universität Frankfurt): Hard
Lefschetz theorem and Hodge-Riemann relations for convex
valuations
15:30-16:00 Break
16:00-17:00 Manoel
Zanoelo Jarra (Universität Groningen): Category of matroids with coefficients
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________