# International Day of Women in Math

**Colloquium of all-female speakers:**
Annika Burmester (University of Bielefeld)

**Titel:**Multiple zeta values, q-analogs, and Hopf algebra structures

**Abstract:** Multiple zeta values extend special values of the Riemann zeta function. I will explain their algebraic structure, which is essentially derived from two distinct product expressions. In particular, I will outline how to obtain a Hopf algebra structure on multiple zeta values.
This will motivate our study of multiple q-zeta values. These are q-series, which degenerate to multiple zeta values under the limit q to 1 and have a strong connection to multiple Eisenstein series. More precisely, I will compare their algebraic structure to the one of the multiple zeta values. In the end, I will sketch my progress made towards a Hopf algebra structure on multiple q-zeta values.

Azul Fatalini (University of Münster)

**Title:** Paradoxical sets and the Axiom of Choice

**Abstract:** Paradoxical sets appear in many areas of mathematics. These are sets that are constructed using the Axiom of Choice and are somehow counterintuitive; examples include the Vitali set and the construction in the Banach-Tarski paradox. The main question of my research is whether some fragments of the Axiom of Choice can be recovered from the existence of certain paradoxical sets. I will present a negative answer to this question and introduce the basic ingredients of Set Theory along the way.

Olga Varghese (University of Düsseldorf)

**Title:** On finite quotients of Coxeter groups

**Abstract:** A standard approach to studying infinite groups is through their finite quotients. While this has limitations in general, the set of finite quotients of a Coxeter group encodes important informations about it. We address the following question: For non-isomorphic Coxeter groups $W_\Gamma$ and $W_\Omega$, must $W_\Gamma$ and $W_\Omega$ have different sets of finite quotient groups?

We will provide Coffee and sweets in between the talks.

**Schedule:**
14.15-15.00 Uhr Talk 1

15.00-15.45 Uhr Break

15.45-16.30 Uhr Talk 2

16.30-16.45 Uhr Break

16.45-17.30 Uhr Talk 3

In the words of the May12 initiative

Women in Mathematics:

"The goal of the day is to inspire women everywhere to celebrate their achievements in mathematics, and to encourage an open, welcoming and inclusive work environment for everybody.“

Note that this event is explicitly open to everyone!

10 May 2024 – 14:00 (till 18:00)

Lecture hall 8, Bielefeld University