Info: The AGDM seminar is a joint seminar of the University of Vienna and TU Wien. In winter semesters, we meet on Tuesdays from 15:00 to 16:30 at the University of Vienna. In summer semesters, we meet on Tuesdays from 15:15 to 16:45 at TU Wien.
Since 2025, we use a mailing-list to advertise the seminar. You can register here.
Place: University of Vienna, Oskar-Morgenstern-Platz 1, BZ 09 (first room on the right on the 9th floor)
Time:Tuesday, 15:00-16:30
| Date: | Tuesday 18.11.2025 |
| Title: | Embeddings of weighted projective spaces |
| Speaker: | Fabián Levicán (University of Vienna) |
| Abstract: | Let $X$ be a projective toric variety of dimension $n$ over an arbitrary field and let $L$ be an ample line bundle on $X$. For $k \geq 0$, it is in general difficult to determine whether $L^{\otimes k}$ is very ample and whether it additionally gives a projectively normal embedding. These two properties are equivalent to the very ampleness, respectively normality, of the corresponding polytope. By a result of Ewald-Wessels, both statements are classically known to hold for $k \geq n - 1$. In this talk we study embeddings of weighted projective spaces $\mathbb{P}(a_0, \ldots, a_n)$ via their corresponding simplices. If one weight is equal to one, these are so-called rectangular simplices. In this case, we give multiple criteria (depending on arithmetic properties of the weights $a_i$) to obtain bounds for the power $k$ which are sharp in many cases. We also introduce combinatorial tools that allow us to systematically construct families exhibiting extremal behaviour. These results extend earlier work of Payne, Hering and Bruns-Gubeladze. This is joint work with Praise Adeyemo (U Ibadan) and Dominic Bunnett (TU Berlin) |
Maintaining a respectful environment is essential to fostering meaningful dialogue and intellectual growth. Participants are expected to refrain from any form of disrespectful or inappropriate behaviour, including offensive comments, harassment, or disruptive conduct. Questions and contributions should be constructive, relevant to the topic, and posed in a professional manner that encourages healthy academic exchange. Harassment of any kind—including verbal, moral or physical—will not be tolerated, and all attendees are urged to uphold these principles to ensure a safe and welcoming atmosphere for everyone.
| 25.11.2025 | Joshua Jeishing Wen | |
| 02.12.2025 | Marcus Schönfelder | |
| 09.12.2025 | ||
| 16.12.2025 | Atsuro Yoshida | |
| 13.01.2026 | ||
| 20.01.2026 | Markus Reibnegger | |
| 27.01.2026 | Mona Gatzweiler |
| 11.11.2025 | Nicolas Allen Smoot (University of Vienna) | Some New Examples of Modular Congruence Multiplicities |
| 04.11.2025 | Eva-Maria Hainzl (TU Wien) | Functional equations with catalytic variable 101 |
| 28.10.2025 | Shane Chern (University of Vienna) | The Koutschan-Krattenthaler-Schlosser determinants and their combinatorics |
| 21.10.2025 | Sergio Alejandro Fernandez de Soto Guerrero (TU Graz) | MathMagic: A positroidal action over a deck of cards |
| 14.10.2025 | Christian Krattenthaler (University of Vienna) | Two Topics, Four Lessons |
| 07.10.2025 | Matija Bucic (University of Vienna) | Equiangular lines via improved eigenvalue multiplicity |