Semestr Letni 2026
Prowadzący: prof. dr hab. Tomasz Szemberg
Seminarium odbywa się we wtorki, w godzinach 10:15 — 11:45, w sali 118. Seminarium odbywa się hybrydowo!
| TERMIN | WYKŁADOWCA | TEMAT |
|---|---|---|
| 24 lutego 2026 |
dr hab. Maciej Ulas (IM UJ) |
There are infinitely many Hilbert cubes of dimension 3 in the set of squares |
| 3 marca 2026 |
PhD Graham Keiper |
Splittings of Ideals of Points in P1 × P1
|
| 10 marca 2026 |
dr hab. Michał Kapustka (IM PAN) |
O parzystonodalnych powierzchniach typu K3 |
| 24 marca 2026 |
prof. dr hab. Tomasz Szemberg |
Czy powierzchnia Weddla jest parzystonodalna i co z tego wynika? |
|
9 kwietnia 2026 godz. 13.00 |
Prof. Dr. Mateusz Michalek (Universität Konstanz) |
Tensor asymptotic rank and the Waldschmidt constant of the Segre variety |
| 14 kwietnia 2026 |
TBA |
TBA |
| 21 kwietnia 2026 |
TBA |
TBA |
| 5 maja 2026 |
TBA |
TBA |
| 12 maja 2026 |
TBA |
TBA |
| 19 maja 2026 |
TBA |
TBA |
| 26 maja 2026 |
TBA |
TBA |
| 9 czerwca 2026 |
TBA |
TBA |
| 16 czerwca 2026 |
TBA |
TBA |
Abstract (Splittings of Ideals of Points in P1 × P1): I will discuss recent work done with Elena Guardo (Catania) and Adam Van Tuyl (McMaster) onideals of points in P1 × P1. Let I_X be the bihomogeneous ideal of a set of finite points X ⊆ P1 × P1. We investigate various notions of “splittings” of the ideal I_X, namely finding ideals J and K such that I_X = J +K, where J and K have prescribed algebraic or geometric properties. We pay particular attention to arithmetically Cohen-Macaulay (ACM) sets of points and introduce the framework of ideals of unions of lines and ACM points in P1 × P1 which allows us to better ”split” these ideals. We also discuss some consequences for the graded Betti numbers of IX in terms of these splittings.
Abstract (Tensor asymptotic rank and the Waldschmidt constant of the Segre variety): The asymptotic rank of tensors and its variant, the tensor asymptotic rank, are important quantities associated with a tensor. They have attracted significant attention due to their connections with complexity theory, in particular with fast matrix multiplication.
In this talk we report on ongoing work with Petteri Kaski in which we obtain new upper bounds for the asymptotic rank of general tensors. We also establish connections with the Waldschmidt constant of the Segre variety and compute this constant for the triple product of projective planes.