Upcoming Talks

Title: SAAAA-Seminar
Speaker: ()
Date: 24.05.2025
Room: Faculty of Mathematics and Physics, Jadranska 19, Ljubljana
Abstract:

Dear colleagues,

we kindly invite you to the {\em Seminar on Analysis and Algebra Alpe-Adria (SAAAA)} on 24th May (Ljubljana).


The SAAAA is a newly established, joint seminar between Zagreb, Ljubljana and Graz in both algebra and analysis, with speakers from all three cities.


Date and location:}
24th May (Saturday), 10:00, at the Faculty of Mathematics and Physics, Jadranska 19, Ljubljana.


Schedule:}
The seminar takes place from 10:00-13:30.\newline
There will be six talks à la 30 minutes (3 talks in analysis and algebra, respectively; two speakers from each city).\newline
Afterwards, a joint lunch in a restaurant is organized.


Speakers:}\newline
Roman Bessonov (University of Ljubljana): TBA\newline
Aleksandar Bulj (University of Zagreb): Powers of unimodular homogeneous multipliers\newline
Nina Kamčev (University of Zagreb): Counting regular hypergraphs\newline
Polona Oblak (University of Ljubljana): TBA\newline
Balint Rago (University of Graz): TBA\newline
Petr Siegl (TU Graz): TBA


Registration:}
If you would like to attend, please register by email (nicolussi@math.tugraz.at).


If you have any further questions, please do not hesitate to ask (nicolussi@math.tugraz.at and frisch@math.tugraz.at).


We are looking forward to seeing you in Ljubljana!


With best wishes,
Sophie Frisch and Noema Nicolussi
(SAAAA organizers at Graz)

Zahlentheoretisches Kolloquium

Title: COPRIME-UNIVERSAL QUADRATIC FORMS
Speaker: Matteo Bordignon (University of Milano)
Date: 02.05.2025, 10:00 Uhr
Room: Seminarraum Geometrie 1, Kopernikusgasse 24, 4.OG
Abstract:

Given a prime $p > 3$, we characterize positive-definite integral qua-dratic forms that are coprime-universal for p, i.e. representing all positive integers coprime to p. This generalizes the 290-Theorem by Bhargava and Hanke and extends later works by Rouse (p = 2) and De Benedetto and Rouse (p = 3). When p = 5, 23, 29, 31, our results are conditional on the coprime-universality of specific ternary forms. We prove this assumption under GRH (for Dirichlet and modular L-functions), following a strategy introduced by Ono and Soundararajan, together with some more elementary techniques borrowed from Kaplansky and Bhargava. Finally, we discuss briefly the problem of representing all integers in an arithmetic progression.