## 2018

### Intercity Number Theory Seminar

16 March, Utrecht. Location: Buys Ballotgebouw 161 (Princetonplein 5, 3584 CC Utrecht). Note: at the moment the main entrance of the BBG is closed and you will need to enter the Buys Ballotgebouw via the Koningsbergergebouw (Budapestlaan 4a-b, 3584 CD Utrecht)- 12:30–13:00
- tea break,
In December 2020, Peter Scholze posed a challenge to formally verify the main theorem on liquid ℝ-vector spaces, which is part of his joint work with Dustin Clausen on condensed mathematics. I took up this challenge with a team of mathematicians to verify the theorem in the Lean proof assistant. Half a year later, we reached a major milestone, and our expectation is that shortly we will have completed the full challenge. In this talk I will give a brief motivation for condensed/liquid mathematics, a demonstration of the Lean proof assistant, and discuss our experiences formalizing state-of-the-art research in mathematics.
- 13:00–13:50
- Masha Vlasenko Warsaw, Dwork crystals and related congruences
In December 2020, Peter Scholze posed a challenge to formally verify the main theorem on liquid ℝ-vector spaces, which is part of his joint work with Dustin Clausen on condensed mathematics. I took up this challenge with a team of mathematicians to verify the theorem in the Lean proof assistant. Half a year later, we reached a major milestone, and our expectation is that shortly we will have completed the full challenge. In this talk I will give a brief motivation for condensed/liquid mathematics, a demonstration of the Lean proof assistant, and discuss our experiences formalizing state-of-the-art research in mathematics.
- 14:00–14:50
- Diego Izquierdo Paris, On a conjecture of Kato and Kuzumaki
In December 2020, Peter Scholze posed a challenge to formally verify the main theorem on liquid ℝ-vector spaces, which is part of his joint work with Dustin Clausen on condensed mathematics. I took up this challenge with a team of mathematicians to verify the theorem in the Lean proof assistant. Half a year later, we reached a major milestone, and our expectation is that shortly we will have completed the full challenge. In this talk I will give a brief motivation for condensed/liquid mathematics, a demonstration of the Lean proof assistant, and discuss our experiences formalizing state-of-the-art research in mathematics.
- 15:00–15:30
- tea break,
- 15:30–16:20
- Sara Checolli Grenoble, On some arithmetic properties of Mahler functions
- 16:30–17:20
- Jakub Byszewski Kraków, Sparse generalised polynomials and automatic sequences

### Intercity Number Theory Seminar

20 April, Groningen. Bernoulliborg, room 165, start at 11:45.- 11:45–12:45
- Maarten Derickx Groningen, Torsion subgroups of rational elliptic curves over infinite extensions of Q.
- 13:30–14:30
- Pınar Kılıçer Oldenburg, On primes dividing the invariants of Picard curves
- 14:45–15:45
- Harm Voskuil Amsterdam, Mumford curves in positive characteristic.
- 16:00–17:00
- Florian Hess Oldenburg, Explicit isomorphisms and fields of definition and moduli of curves

### Intercity Number Theory Seminar

22 June, Leiden. This is the last day of the workshop Effective Methods for Diophantine Problems. All talks will be in the Havingazaal of the Gorlaeus Building, located on the first floor of what's indicated by LMUY on this map and the detailed map on the last page of that document. Note that you can not get there through the main entrance of the Gorlaeus Lecture Hall, indicated by (4) on the map.### Belgian-Dutch Algebraic Geometry seminar

20 September, Nijmegen. This is a two-day event: September 20 and 21. See the website, also for (free) required registration.### Aachen-Bonn-Koeln-Lille-Siegen seminar on automorphic forms

23 November, Utrecht. Location: Minnaert Building, room 201- 13:15–14:15
- Peter Bruin Leiden, On explicit computations with modular Galois representations
- 14:15–15:15
- Alexandru Ciolan Köln, Asymptotics and inequalities for partitions into squares
- 15:45–16:45
- Jan-Willem van Ittersum Utrecht, A symmetric Bloch-Okounkov theorem
- 16:45–17:45
- Annalena Wernz Aachen, On Hermitian modular forms - Theta series and Maass spaces

### Intercity Seminar Number Theory

7 December, Eindhoven. In Metaforum 14 (6e verdieping); PhD defense Guus Bollen in Senaatszaal of Auditorium.- 11:45–12:30
- Wieb Bosma Nijmegen, Enumerating self-complementary graphs
- 13:15–14:00
- Winfried Hochstättler Hagen, The Varchenko Determinant of an Oriented Matroid
- 14:15–15:00
- Dustin Cartwright Tennessee, One-dimensional groups and algebraic matroids
- 16:00–17:00
- Guus Bollen Eindhoven, PhD defense

### Intercity Number Theory Seminar

18 December, Leiden. In Snellius 412; PhD defense Erik Visse in the Academiegebouw in the center of Leiden.- 10:00–11:00
- Erik Visse Leiden, PhD defense
- 13:45–14:45
- Rachel Newton Reading, Number fields with prescribed norms
- 15:00–16:00
- Daniel Loughran Manchester, Integral points on Markoff surfaces
- 16:15–17:15
- Efthymios Sofos Bonn, The size of the primes
*p*for which a Diophantine equation is not soluble modulo*p*