Thursday, April 23, 2026
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Joyce's Wallcrossing Result, free slot
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
13:00-14:00
HFG 707
Applied Math Seminar
Mark van den Bergh (Leiden University)
host: Willemien
14:30-15:30
HFG 7.07
AG Seminar
Philip Engel (University of Illinois Chicago)
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, April 24, 2026
15:00-17:00
HFG 707
Friday Fish
Douwe Hoekstra - Convex integration implies holonomic approximation
Massot and Theillière showed how one can prove the holonomic approximation lemma using convex integration in the case of first-order jet bundles. In this talk we will discuss a generalization of this idea to higher-order jet bundles using the simplest non-trivial case as a leading example. We will discuss the problems one encounters when trying to generalize this approach and how to solve them. In particular, we will touch upon extending sections of a jet bundle holonomically from a submanifold to an open neighbourhood thereof and a mixed-order version of convex integration.
Saturday, April 25, 2026
14:00-17:00
KBG
A-eskwadraat - Lustrum Year Reunion

Op 25 april organiseert A–Eskwadraat eenreünie voor al haar (oud-)leden. Voor deze editie leek het ons heel leuk als erook docenten rondlopen tijdens de borrel met wie zij mee kunnen praten. Bij deborrel zal onze borrelcommissie zorgen voor een goede voorraad(speciaal)biertjes, wijn en fris en er zullen ook percolators met koffie enthee aanwezig zijn.
Mocht het je leuk lijken om met oud-studenten te praten, dan lijkt het onshartstikke leuk als je komt. Je bent welkom vanaf 14u en het duurt tot 17u. Hetzal plaatsvinden in de hal van het KBG en je kunt je aanmelden met de volgendelink:

https://forms.gle/riwpauWRe7sSF2y78

Er is ook lunch vanaf 13u. Mocht je mee willenlunchen, dan is dat € 5,- vanaf 13 u. Dit kun je aangeven in de formshierboven. Ben je ook oud-lid van A–Eskwadraat en wil je de hele reüniebijwonen, dan kun je je aanmelden met de volgende link:

https://docs.google.com/forms/d/e/1FAIpQLSe9uJBCTDcPkEPK1h88t2pm230MlqF9CmOJlikzAopDitS4ew/viewform?usp=dialog

Monday, April 27, 2026
15:00-17:00
7.07 HFG
Category theory seminar
TBA - TBA
Tuesday, April 28, 2026
11:00-12:00
HFG 7.07
NT Seminar
Alexandra Shlapentokh (Using units to define Z)
Abstract: We show how to use units of rings of integers to define Z over these rings in many infinite algebraic extensions of Q.  This talk is based on joint work with B. Mazur and K. Rubin.
13:30-14:30
HFG 7.07
AG Seminar
Yagnaseni Dutta (Leiden University)
15:15-17:00
KBG Atlas
Mathematics department Day & Best TA and lecturer award
16:00-17:00
HFG 7.07
UGC colloquium
Maarten de Hoop (Rice University) - Acousto-gravitational spectra, singular geometry and inverse problems on gas giants
On gas giant planets, the speed of sound is isotropic and tends to zero at the surface. Geometrically, this corresponds to a Riemannian manifold whose metric tensor has a conformal blow-up near the boundary. The blow-up is tamer than in asymptotically hyperbolic geometry: The boundary is at a finite distance.

We consider the acoustic wave and the acousto-gravitational equations of gas giants. The geometry of acoustic waves is modeled by the above mentioned singular Riemannian, "gas giant" metric. We give an overview of the basic properties of the geometry, including properties of geodesics near the boundary, the Hausdorff dimension of the boundary, and the discreteness of the (acoustic) spectrum of the Laplace–Beltrami operator. We present the spectral analysis of this operator and derive the Weyl law. The involved exponents depend on the Hausdorff dimension, which, in the supercritical case (the relevant case for Jupiter and Saturn), is larger than the topological dimension. The Weyl asymptotics determines the blow-up in the supercritical case.

We then consider various inverse problems for simple gas giant planets, proving that the metric is uniquely determined by its boundary distance data and that the geodesic ray transform is injective. We study the determination of a conformal factor of the metric from boundary data (rigidity) using methods involving singular microlocal analysis of the normal operator corresponding to the geodesic ray transform. Moreover, we present the boundary observability of acoustic waves given full and local observations and show how the resulting observability inequality can be turned into a scanning protocol where the observation set moves in time. We conclude with some remarks on inertia-gravity modes on gas planets forming the essential spectrum.

Joint research with Y. Colin de Verdìère, C. Dietze, J. Ilmavirta, A. Kykkänen, R. Mazzeo and E. Trélat.
Thursday, April 30, 2026
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Examples Session, free slot
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Tuesday, May 5, 2026
13:30-14:30
HFG 7.07
AG Seminar
Thursday, May 7, 2026
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Boijko's construction, Pim
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
13:00-14:00
HFG 611
Applied Math Seminar with Nicoleta Cazacu (Ecole Polytechnique)

Title: Quantitative uniform-in-time propagation of chaos for stochastic particle systems interacting through L^p kernels

Abstract: Deriving macroscopic evolution equations from interacting particle systems is a classical problem in mathematical physics. In the mean-field regime, such systems are expected to converge, as the number of particles tends to infinity, to solutions of nonlinear Fokker-Planck equations. One particular challenge is to establish whether this convergence holds uniformly in time, especially for systems with singular interaction kernels.
In this talk, we first briefly review recent results establishing uniform-in-time propagation of chaos. We then introduce the framework of mollified interacting particle systems. Finally, we discuss recent work establishing quantitative uniform-in-time propagation of chaos for interaction kernels in L^p (p>d). The approach is based on a mild formulation of the limiting equation together with semigroup estimates.
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, May 8, 2026
11:00-16:00
JKH 2-3, room 110
Mark Kac seminar in mathematical physics and probability with Elena Agliari (U Rome) and Edan Lerner (UvA)
Speaker morning (11-12.45): Elena Agliari (U Rome)

Title: TBA

Abstract: TBA




Speaker afternoon (14.15 - 16.00): Edan Lerner (UvA)

Title: Mechanical Criticality in Jamming Transitions

Abstract: Jamming transitions include a broad class of nonequilibrium mechanical phenomena in which material systems transition abruptly between floppy or fluid to rigid or solid phases. In my lecture I will review some of the recent theoretical and computational advancements towards understanding jamming transitions in soft matter systems. Starting from the simplest system of disordered spring networks, I will then describe the mechanics of soft-sphere packings, the rheology of dense non-Brownian suspensions, and finally the stiffening of biopolymer networks subjected to large deformations. I will show how the scaling behavior near the respective jamming transitions of these systems can be obtained by perturbing their respective critical states.
15:00-17:00
HFG 707
Friday Fish
Jaime Pedregal Pastor - TBA
TBA
Monday, May 11, 2026
15:00-17:00
7.07 HFG
Category theory seminar
TBA - TBA
Tuesday, May 12, 2026
13:30-14:30
HFG 7.07
AG Seminar
16:00-17:00
HFG 7.07
MI talk
Linda Cook - TBA
TBA
Thursday, May 14, 2026
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Virtual Classes of Hilbert Schemes of Points, Tomás
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, May 15, 2026
12:30-14:00
HFG 7.07
HoM colloquium talks
Nicolas Michel “Concepts, words, and signs - Eduard Study and the algebraization of geometrical mechanics”
Monday, May 18, 2026
15:00-16:30
HFG 7.07
HoM colloquium talk
Nicolas Michel
Tuesday, May 19, 2026
13:30-14:30
HFG 7.07
AG Seminar
Thursday, May 21, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Monday, May 25, 2026
15:00-17:00
7.07 HFG
Category theory seminar
TBA - TBA
Tuesday, May 26, 2026
13:30-14:30
HFG 7.07
AG Seminar
Thursday, May 28, 2026
12:00-13:00
Hfg 707
Math-Phys Thursday with Max Willems
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Examples Session, Pim & Tomás
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, May 29, 2026
11:00-13:00
HFG 707
Friday Fish
Ashkan Sadat Kyaee - TBA
TBA
15:00-17:00
HFG 707
Friday Fish
Lucas Dahinden - TBA
TBA
Tuesday, June 2, 2026
13:30-14:30
HFG 7.07
AG Seminar
Sièna van Schaick (Radboud University)
16:00-17:00
HFG 6.11
MI talk
Francesca Pratali
TBA
Thursday, June 4, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, June 5, 2026
15:00-17:00
HFG 707
Friday Fish
Peter Hochs (RU) - TBA
TBA
Monday, June 8, 2026
15:00-17:00
7.07 HFG
Category theory seminar
TBA - TBA
Tuesday, June 9, 2026
13:30-14:30
HFG 7.07
AG Seminar
Arkadij Bojko (SIMIS)
Thursday, June 11, 2026
12:00-13:00
Hfg 707
Math-Phys Thursday
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
The Vertex Algebra in equivariant geometry, Arkadij
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Tuesday, June 16, 2026
13:30-14:30
HFG 7.07
AG Seminar
Ander Arriola Corpion (University of Groningen)
Thursday, June 18, 2026
13:00-14:30
HFG 7.07
Wallcrossing Techniques in Algebraic Geometry seminar
Examples Session, Arkadij
Further details and meeting link: https://www.uu.nl/staff/TManopulo/Extra2
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Friday, June 19, 2026
15:00-17:00
HFG 707
Friday Fish
Michael Jung (VU) - TBA
TBA
Monday, June 22, 2026
15:00-17:00
7.07 HFG
Category theory seminar
TBA - TBA
Tuesday, June 23, 2026
13:30-14:30
HFG 7.07
AG Seminar
Thursday, June 25, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Tuesday, June 30, 2026
13:30-14:30
HFG 7.07
AG Seminar
Thursday, July 2, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Tuesday, July 7, 2026
14:15-15:15
Academiegebouw
PhD defense Sebastián Carrillo Santana
Thursday, July 9, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, July 16, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, July 23, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, July 30, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, August 6, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, August 13, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, August 20, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, August 27, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, September 3, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, September 10, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, September 17, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, September 24, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, October 1, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, October 8, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!
Thursday, October 15, 2026
17:30-21:30
HFG Library
Loki - Lean formalization meeting
Named after the Dutch god of formalization, in the Loki meetings we formalize diverse areas of math. Newcomers welcome!