Martin Bright is associate professor and programme director in the Mathematical Institute of Leiden University. He received his PhD from the University of Cambridge in 2002. After positions in Liverpool, Bristol, Warwick and Beirut, he moved to Leiden in 2014. His research interests are centred around local-global principles and the Brauer–Manin obstruction, including computational aspects.

Valentijn Karemaker is an assistant professor at Utrecht University who joined the Mathematical Institute in 2019, having previously worked in the United States and Sweden. Her research is in arithmetic geometry and will be funded by an NWO Vidi grant from 2024. Currently she is most interested in arithmetic properties and moduli spaces of (supersingular) varieties and Drinfeld modules over finite fields. Other projects have involved local-global principles for rational points on varieties, arithmetic dynamics, anabelian geometry, and Galois representations. She is committed to increasing diversity and inclusion in mathematics and science, e.g. via Women in Numbers, European Women in Mathematics, and the Utrecht Young Academy.

Ronald van Luijk is a professor of mathematics at Leiden University. Within the field of rational points, Van Luijk’s research focuses on the distribution of rational points on algebraic surfaces, in particular K3 surfaces and del Pezzo surfaces. After doing his master’s at Utrecht University, he received his PhD from the University of California, Berkeley, in 2005. He held positions at CRM (Montreal), MSRI (Berkeley), PIMS (Vancouver), Universidad de los Andes (Bogotá), Warwick University, EPFL (Lausanne), and received an NWO Vidi grant in 2012.

Steffen Müller joined the Bernoulli Institute at the University of Groningen as an assistant professor in 2017, after a postdoc position in Hamburg and a junior professorship in Oldenburg. He obtained his PhD from Bayreuth. Steffen works on explicit methods in arithmetic geometry of curves and abelian varieties, specialising in height functions and p-adic analytic techniques. Much of his recent work has centered on p-adic heights and explicit non-abelian Chabauty, and applications thereof to rational points on modular curves.

Marta Pieropan is an assistant professor at Utrecht University. She received her PhD from Leibniz University Hannover in 2015, and then held postdoctoral positions at Free University Berlin and at EPFL. Her research focuses on the arithmetic of Fano varieties and log Fano pairs, and on counting techniques for the distribution of rational points over global fields. Her research interests include rationally connected varieties, toric varieties, arithmetic applications of birational geometry and of logarithmic geometry, moduli spaces of stable (log) curves, special subsets of rational points such as Campana points.

Cecília Salgado is an associate professor in the Algebra Group of the Bernoulli Institute at the University of Groningen. After concluding her Ph.D. in Paris VII, she was a postdoctoral researcher at Leiden and Bonn before taking a position at the Federal University of Rio de Janeiro, where she is now also an associate professor. Her research is currently around the arithmetic and geometry of algebraic surfaces, in particular those with fibration structures. She is also interested in manifestations of those in the context of algebraic geometry codes. She strives for a diverse community in mathematics and has been involved in several initiatives as the European editions of Women in Numbers and also the organisation of events in Brazil and more recently in Groningen.

## Members

Victor de Vries is a Ph. D. student at Leiden University, working under the supervision of Ronald van Luijk. His current research interests include local to global principles for Campana points and the Brauer-Manin obstruction.

Riya Parankimamvila Mamachan joined the Bernoulli Institute at the University of Groningen as a Ph.D. candidate in September 2023 under the supervision of Steffen Müller. After completing a BS-MS Dual degree with a major in Mathematics from the Indian Institute of Science Education and Research, Tirupati, she joined the ALGANT Masters Programme 2021-2023. As a part of this programme, she spent her first year at the University of Duisburg-Essen and the second year at the University of Padova. Her master thesis was about studying mathematical aspects of the Castryck-Decru key recovery attack on SIDH. Currently, she is studying explicit Chabauty for surfaces.

Soumya Sankar is a postdoc at the Mathematical Institute at Utrecht University. She finished her Ph. D. in 2020 at the University of Wisconsin-Madison under the supervision of Jordan Ellenberg. She subsequently held postdoctoral positions at MSRI and at Ohio State University. Her research interests include arithmetic statistics, understanding rational points on stacks, and questions on rationality over non-algebraically closed fields. She is particularly interested in understanding the arithmetic of moduli spaces and the distribution of rational points on them.

Justin Uhlemann is a Ph.D. candidate of the Mathematical Institute at Utrecht University, working under the supervision of Marta Pieropan. He previously finished his Master’s at the Leibniz University in Hannover. His research interests lie at the intersection of analytic number theory and arithmetic geometry. This includes questions about the asymptotic behavior of rational points of bounded height on projective varieties, Campana points, and obstructions to local-global principles.

Lara Vicino is a postdoctoral researcher in the Algebra Group of the Bernoulli Institute at the University of Groningen. She received her PhD in January 2024 from the Technical University of Denmark, where she studied under the supervision of Peter Beelen and Maria Montanucci. Her research interests include algebraic curves over finite fields, in particular Weierstrass semigroups, automorphisms of curves, and applications in coding theory. Within the consortium framework, she is currently working on locally recoverable codes from higher-dimensional varieties.

Hsin-Yi Yang is a Ph.D. student at the Mathematical Institute at Utrecht University, working under the supervision of Valentijn Karemaker. She graduated from the ALGANT program in 2023, as a part of which she attended Universität Duisburg-Essen and Université Paris-Saclay, respectively. Her research interests lie in algebraic number theory and arithmetic geometry and she is currently studying abelian varieties over finite fields and related topics.

Haowen Zhang is a postdoctoral researcher at Leiden University since September 2023. He received his PhD in Paris in 2023 under the supervision of Cyril Demarche, for his work on weak and strong approximation problems of homogeneous spaces of algebraic groups over certain function fields. Before that, he was a student at the Ecole Normale Supérieure in Paris.

## Affiliated Members

Mar Curcó-Iranzo is a PhD candidate at Utrecht University since October 2020. She works under the supervision of Valentijn Karemaker. Her research is in arithmetic geometry of modular curves. Her main project concerns torsion points on (generalized) Jacobians of modular curves and Drinfeld modular curves. She has also taken part in projects related to Diophantine equations. She believes in Federico Ardila’s axioms on inclusion and diversity in mathematics, and takes an active role in outreach and university governance, for example by organizing the event “A PhD, is that for me?” and as a member of the GSNS PhD council.

João Paulo Guardieiro Sousa is a double degree Ph.D. student from ICMC (Universidade de São Paulo at São Carlos, Brazil) under the supervision of Herivelto Borges and University of Groningen under the supervision of Cecília Salgado. He graduated and did his Master studies at Universidade Federal de Uberlândia (UFU) in Brazil. He is interested in many topics on Finite Fields theory, such as permutation polynomials and q-polynomials. He is currently studying the Frobenius classicality of curves and elliptic curves and surfaces.

Tianci Kang is a PhD student at the University of Groningen under the supervision of Steffen Muller since November 2023. He finished his Master’s at the Capital Normal University in Beijing. His master thesis was about Arakelov theory on arithmetic surfaces. Currently, his research interests lie in p-adic heights and Arakelov theory on Abelian varieties.

Timo Keller is currently a Marie Skłodowska-Curie postdoctoral fellow in Groningen. He works on questions around abelian varieties and curves over arithmetic fields. In particular, he is interested in the Birch–Swinnerton-Dyer conjecture (explicit methods over number fields, Iwasawa theory, and in positive characteristic) and rational points on modular curves.

Martin Lüdtke is a postdoctoral researcher in the Algebra Group of the Bernoulli Institute at the University of Groningen. He joined the institute in 2021 to work with Steffen Müller after obtaining his PhD in Frankfurt. His research focus lies on the arithmetic of fundamental groups, in particular the non-abelian Chabauty method for finding rational or S-integral points on hyperbolic curves, and questions of anabelian geometry such as Grothendieck’s Section Conjecture.

Sara Mehidi is a postdoc at the Mathematical Institute at Utrecht University, working with Marta Pieropan. She finished her Phd in 2022 at the Universities of Toulouse and Bordeaux, under the supervision of Jean Gillibert and Dajano Tossici, where she studied the problem of extending torsors in the logarithmic setting. She subsequently held a postdoctoral position in Bordeaux. Her research interest include logarithmic geometry, enumerative geometry and more recently, their applications to arithmetic. With Marta Pieropan, she aims to study Campana points under a new framework using the language of log geometry.

Boaz Moerman is a PhD student at Utrecht University under the supervision of Marta Pieropan since September 2021. His research interests focuses on special subsets of rational points (W-points), such as Campana points, over both number fields and function fields. For these subsets he studies analogs of strong approximation and the distribution of such points on toric varieties. His interests also include the relationship of W-points and stacks.

Wim Nijgh is a PhD student at Leiden University since February 2022, working under the supervision of Ronald van Luijk. His research focuses on the arithmetic and geometry of algebraic surfaces, currently focusing on del Pezzo, K3, and elliptic surfaces. His master thesis was about the Zariski density of the rational points on a family of del Pezzo surfaces of degree 1.

Margherita Pagano is a PhD student at Leiden University since September 2020. She works under the supervision of Martin Bright. Her research interests are mainly in arithmetic geometry, working on rational points on varieties. She mostly focuses on the Brauer-Manin obstruction to weak approximation, with particular emphasis on K3 surfaces.

Leonie Scherer is a PhD student working under the supervision of Jakob Stix and Valentijn Karemaker. She is mainly located at Goethe University Frankfurt in Germany.

Her master’s thesis was about generators and relations of the étale fundamental group. Leonie is working on arboreal Galois representations and the étale fundamental group.

Manoy Trip is a PhD student at the University of Groningen, in the Algebra group of the Bernoulli Institute. She works under supervision of Cecília Salgado. She completed her BSc and MSc in mathematics at the University of Groningen as well. Her master thesis was about p-adic height functions on Jacobians of genus 2 curves, which she did under supervision of Steffen Müller and Francesca Bianchi. Her PhD project is on the arithmetic and geometry of algebraic surfaces, currently focusing on del Pezzo surfaces of degree 1.