Special Year 2024-25: Algebraic and Geometric Combinatorics - Seminar

Special Year Seminar I

December 11, 2024 | 2:00pm - 3:00pm

Influential work of Hodge from the 1940s led the way in using Gröbner bases to combinatorially study the Grassmannian. We follow Hodge's approach to investigate certain subvarieties of the Grassmannian, called positroid varieties. Positroid...

Special Year Seminar

December 09, 2024 | 2:30pm - 3:30pm

The theme of the lecture is the notion of points over F1, the field with one element. Several heuristic computations led to certain expectations on the set of F1-points: for example the Euler characteristic of a smooth projective complex variety X...

Special Year Seminar II

December 05, 2024 | 10:00am - 12:00pm

Schubert Calculus studies cohomology rings in (generalized) flag varieties, equipped with a distinguished basis - the fundamental classes of Schubert varieties - with structure constants satisfying many desirable properties. Cotangent Schubert...

Special Year Seminar I

December 04, 2024 | 2:00pm - 3:00pm

Vertex decomposition, introduced by Provan and Billera in 1980, is an inductive strategy for breaking down and understanding simplicial complexes. A simplicial complex that is vertex decomposable is shellable, hence Cohen--Macaulay. Through the...

Special Year Seminar

November 25, 2024 | 1:00pm - 2:00pm

A class of tensors, called "concise (m,m,m)-tensors  of minimal border rank", play an important role in proving upper bounds for the complexity of matrix multiplication. For that reason Problem 15.2 of "Algebraic Complexity Theory" by Bürgisser...

Special Year Seminar

November 25, 2024 | 10:00am - 11:00am

Chapter 14 of the classic text "Computational Complexity" by Arora and Barak is titled "Circuit lower bounds: complexity theory's Waterloo". I will discuss the lower bound problem in the context of algebraic complexity where there are barriers...

Special Year Seminar II

November 14, 2024 | 11:00am - 12:00pm

The theme of the third lecture is the notion of points over F1, the field with one element. Several heuristic computations led to certain expectations on the set of F1-points: for example the Euler characteristic of a smooth projective complex...

Special Year Seminar II

November 14, 2024 | 10:00am - 11:00am

The second lecture features the nuts and bolts of the invariants from first lecture, which we call foundations. We explain the structure theorem for foundations of ternary matroids, which is rooted in Tutte's homotopy theorem. We show how this...

Special Year Seminar I

November 13, 2024 | 2:00pm - 3:00pm

Lecture Series Framework:  A unifying framework for F1-geometry, tropical schemes and matroid theory. In this series of 3 lectures, I will present a recent approach towards F1-geometry and its links to tropical geometry, matroid theory, Lorentzian...