Thursday, 24 April
03:00 pm
Bielefeld University V2-210/216
Equations in groups: between decidability and undecidability
Speaker: Laura Ciobanu
For a group or semigroup or ring G, solving equations where the coefficients are elements in G and the solutions take values in G can be seen as akin to solving systems of linear equations in linear algebra, Diophantine equations in number theory, or more generally, polynomial systems in algebraic geometry.
In this talk I will give a survey about solving equations in infinite non-abelian groups, with emphasis on free groups, and show how imposing certain constraints on the solutions can tilt the balance between decidability and undecidability.
Wednesday, 30 April
02:15 pm
Bielefeld University V2-210/216
How to tropicalize algebraic groups (and why we should care)
Speaker: Martin Ulirsch
Tropical geometry studies a piecewise linear combinatorial shadow of classical algebraic geometry. In this talk I will explain what little we currently know about the tropical geometry of algebraic groups. Different avenues of progress towards an answer to this question lead to new insights both within and beyond tropical geometry, in particular in the context of vector bundles and the geometry of buildings. This talk will touch upon joint work with Luca Battistella, Desmond Coles, Andreas Gross, Inder Kaur, Kevin Kühn, Arne Kuhrs, Annette Werner, Alejandro Vargas, and Dmitry Zakharov.
Friday, 2 May
01:15 pm
Bielefeld University B2-278
Quiver Grassmannians for the Bott-Samelson resolution of type A Schubert varieties
Speaker: Giulia Iezzi
Quiver Grassmannians are projective varieties parametrising subrepresentations of quiver representations. Their geometry is an interesting object of study, due to the fact that many geometric properties can be studied via the representation theory of quivers. In this talk, we construct a special quiver with relations and consider two classes of quiver Grassmannians for this quiver. For an appropriate choice of dimension vector for this quiver, we provide an isomorphism between the corresponding quiver Grassmannians and certain Bott-Samelson resolutions of type A Schubert varieties. Furthermore, for smooth type A Schubert varieties, we identify a suitable dimension vector such that the corresponding quiver Grassmannian is isomorphic to the Schubert variety.
Thursday, 15 May
04:00 pm
Bielefeld University V2 210/216
Algebraic K-theory and chromatic homotopy theory
Speaker: Markus Land
05:15 pm
Bielefeld University V2 210/216
From problems of linear algebra via moduli spaces and their invariants to lattice combinatorics
Speaker: Markus Reineke
We discuss unsolved problems of linear algebra and how they can be encoded in moduli spaces. We then review some typical results and conjectures on invariants of such moduli spaces, resulting in potential applications to Tamari lattices.