## 2017

### Mini-workshop arithmetic & moduli of K3 surfaces

31 January, UvA Amsterdam. Programme. Registration is compulsary.- Martin Orr Imperial College,
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.
- Tony Várilly-Alvarado Rice University,
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.
- Alexei Skorobogatov Imperial College,
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.
- Bianca Viray University of Washington, Seattle,

### Intercity Number Theory Seminar

10 March, Leiden. Snellius building, room 407/409- 13:30–14:30
- Carlo Pagano Uiversiteit Leiden, Distribution of ray class groups: 4-ranks and general model
- 14:45–15:45
- Peter Koymans Universiteit Leiden, On the equation
*x*+*y*= 1 in finitely generated groups in positive characteristic - 16:00–17:00
- Robin de Jong Universiteit Leiden, New results of effective Bogomolov-type for cycles on jacobians

### intercity Number Theory Seminar

24 March, Utrecht. Marinus Ruppertgebouw (Leuvenlaan 21, 3584 CE Utrecht), room: Paars- 13:00–13:50
- Lin Weng Kyushu University / MPIM Bonn, Non-Abelian Zeta Functions And Their Zeros
- 14:00–14:50
- Hatice Boylan İstanbul Üniversitesi / MPIM Bonn, Fourier coefficients of Jacobi Eisenstein series over number fields
- 15:15–16:05
- Cyril Demarche Paris 6 - ENS, Local-global principles for homogeneous spaces
- 16:15–17:05
- Jehanne Dousse Universität Zürich, Refinement of partition identities and the method of weighted words

### Intercity Number Theory Seminar

7 April, Groningen. Bernoulliborg 105- 12:00–13:00
- Mark Jeeninga Groningen, Lenstra's epsilon: A curious periodicity in RevLex field extensions of degree
*p*over*F*_{p}. - 13:30–14:30
- Ricardo Buring Groningen, Relations among Kontsevich graph weight integrals.
- 14:45–15:45
- Jan Steffen Müller Oldenurg, Computing canonical heights on elliptic curves in quasi-linear time.
- 16:00–17:00
- Ulrich Derenthal Hannover, Manin's conjecture for a family of nonsplit del Pezzo surfaces

### Intercity Number Theory Seminar

21 April, Nijmegen. Linnaeusgebouw, Heyendaalseweg 137, 6525 AJ, Nijmegen - room LIN7- 11:30–12:30
- Lars Halle Copenhagen, Motivic zeta functions of degenerating Calabi-Yau varieties
- 13:45–14:45
- Giuseppe Ancona Strasbourg, Standard conjectures for abelian fourfolds
- 15:15–16:15
- Yohan Brunebarbe Zürich, Hyperbolicity of moduli spaces of abelian varieties
- 16:30–17:30
- Olivier Wittenberg Paris, Zero-cycles on homogeneous spaces of linear algebraic groups

### Intercity Number Theory Seminar

19 May, UvA and VU Amsterdam. All lectures are in room A1.10, at Science Park 904.- 11:00–12:00
- Ana Caraiani Bonn, Galois representations and torsion classes
- 13:00–14:00
- Arne Smeets Njmegen, Pseudo-split fibres and the Ax-Kochen theorem
- 14:30–15:30
- Maxim Mornev Leiden & Amsterdam, Shtuka cohomology and special values of Drinfeld modules
- 16:00–17:00
- Jeroen Sijsling Ulm, Computing endomorphisms of Jacobians

### Intercity Number Theory Seminar

3 November, UvA and VU Amsterdam. All talks will be in the main building (Hoofdgebouw) at the VU Campus. The first talk in room HG-05A24 followed by two talks in room HG-15A16. Lunch will be provided in the latter room before the start of the second talk.- 12:05–12:50
- Julie Desjardins Bonn, Density of rational points on elliptic surfaces
- 13:15–14:00
- Jan Tuitman Leuven, An update on effective Chabauty
- 14:05–14:50
- Giulio Orecchia Leiden, A monodromy criterion for existence of Neron models

### Intercity Number Theory Seminar

17 November, Leiden. Snellius, room 312. (The Snellius restaurant will be closed; the restaurants in the Huygens and Gorlaeus buildings are open.)- 13:00–14:00
- Reinier Bröker Brown University, Lower bounds for Hilbert class polynomials
- 14:30–15:30
- Christopher Lazda Universiteit van Amsterdam, A Néron-Ogg-Shafarevich criterion for K3 surfaces
- 15:45–16:45
- Nils Bruin Simon Fraser University, Genus 2 Jacobians with full level 3 structure