## 2019

### Intercity Number Theory Seminar

1 March, Groningen. The first talk takes place in room 165 of the Bernoulliborg and the three other talks take place in room 253.- 12:00–13:00
- Dino Festi Mainz, A method to compute the geometric Picard lattice of a K3-surface of degree 2
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.
- 13:45–14:45
- Florian Hess Oldenburg, Partially euclidean global fields
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.
- 15:00–16:00
- Marc Paul Noordman Groningen, Algebraic first order differential equations
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.
- 16:15–17:15
- Jan Vonk Oxford, Singular moduli for real quadratic fields

### Intercity Number Theory Seminar

15 March, Utrecht. The morning lecture takes place in KGB Atlas (Koningsbergergebouw Budapestlaan 4a-b, 3584 CD Utrecht) and in the afternoon we are in MIN 2.01 (Minnaertgebouw Leuvenlaan 4, 3584 CE Utrecht).- 11:00–12:00
- Efrat Bank Technion, Israel, Primes in short intervals on curves over finite fields
- 13:15–14:15
- Francesca Balestrieri MPIM Bonn, Germany, Arithmetic of zero-cycles on products of Kummer varieties and K3 surfaces
- 14:15–15:15
- Kęstutis Česnavičius Orsay, France, Macaulayfication of Noetherian schemes
- 15:30–16:30
- Judith Ludwig Heidelberg, Germany, Perfectoid Shimura varieties and applications

### Intercity Number Theory Seminar

28 March, Leiden. This is a**Thursday**. All talks will be held in the Pieter de la Courtgebouw, room A5-47, which is walking distance from the train station. The PhD defense of Anna Somoza takes place in the Academiegebouw.

- 11:00–12:00
- Christophe Ritzenthaler Rennes, Reduction of plane quartics
- 12:45–13:45
- Pınar Kılıçer Groningen, Modular invariants for genus-3 hyperelliptic curves
- 14:00–15:00
- Elisa Lorenzo-García Rennes, Modular expressions for Shioda invariants
- 16:15–17:15
- Anna Somoza Leiden, PhD defense

### Seminarium Computer Algebra Nederland / Intercity Number Theory Seminar

12 April, UvA Amsterdam. The first three lectures will be in room C0.110 in Science Park 904. Tim Dokchitser's inaugural lecture will be in the Aula.- 10:15–11:15
- Steffen Löbrich UvA, On cycle integrals of meromorphic modular forms
- 11:30–12:30
- Alex Bartel Glasgow, Torsion homology and regulators of isospectral manifolds
- 13:30–14:30
- Maarten Derickx MIT, Modularity of elliptic curves over totally real cubic fields
- 16:00–17:00
- Tim Dokchitser Bristol / UvA, Inaugural lecture

### Intercity Number Theory Seminar

10 May, Leiden. The first talk will take place in room B3 of the Snellius building. The afternoon talks take place in room 412 and will be followed by the awarding of the Compositio Prize 2014-2016 to James Maynard, and a reception.- 11:00–12:00
- Guido Lido Leiden, Roma, Computations in the Poincaré torsor and the quadratic Chabauty method
- 13:15–14:15
- Damaris Schindler Utrecht, On prime values of binary quadratic forms with a thin variable
- 14:30–15:30
- Peter Koymans Leiden, The spin of prime ideals and applications
- 15:45–16:45
- James Maynard Oxford, Dense clusters of primes in subsets

### Intercity Number Theory Seminar

6 September, Nijmegen. The morning talks will be held in HG00.307, the informal discussions in leg HG03.07 (3rd floor), and the afternoon talk in room HG00.062.- 11:00–12:00
- Riccardo Pengo Copenhagen, Mahler’s measure and elliptic curves with complex multiplication
- 12:15–13:15
- Alina Ostafe Sydney, On some unlikely intersections for values and orbits of rational functions
- 14:00–15:15
- , informal discussions at math department
- 15:20–16:20
- Berend Ringeling Utrecht, Zeros of modular forms and congruences

### Intercity Number Theory Seminar

18 October, Utrecht. The morning lecture is in Minnaert 201, the first two afternoon lectures In Koningsberger Atlas, and the final lecture in Buys Ballot 001 (all these buildings are connected internally)- 11:00–11:50
- Andrew Schopieray Sydney/Berkeley, Quadratic d-numbers
- 13:15–14:05
- Andrew Bridy Yale, The arboreal finite index problem
- 14:10–15:00
- Jakub Byszewski Krakow, Automatic sequences: structure and randomness
- 15:20–16:10
- Vandita Patel Manchester, A Galois property of even degree Bernoulli polynomials

### Intercity Number Theory

1 November, Leiden. Room 312 of the Snellius building- 11:00–12:00
- Martin Bright Leiden, A walk on the wild side: p-torsion in the Brauer group
- 13:30–14:30
- Leila Schneps Jussieu, Paris, Grothendieck-Teichmüller theory, a crossroads between geometry and number theory.
- 14:50–15:50
- Pierre Lochak Jussieu, Paris, A topological version of Grothendieck-Teichmüller theory.
- 16:10–17:10
- Igor Shparlinski Sydney, Integers of prescribed arithmetic structure in residue classes

### Belgian Dutch Algebraic Geometry Day

8 November, Antwerpen.### Intercity Number Theory Seminar

13 December, UvA and VU Amsterdam. At the VU: before lunch in room WN–S623 and after lunch in room WN–P647 (both in the W&N building).- 11:00–12:00
- Ilke Canakci VU, Cluster algebras and continued fractions
- 13:15–14:15
- David Hansen MPIM Bonn, Completed cohomology and the p-adic Langlands program
- 14:30–15:30
- Joey van Langen VU, Automating the modular method for Frey Q-curves
- 16:00–17:00
- Lars Kühne University of Basel, The Equidistribution Conjecture for semiabelian varieties