13th October 2026: Mahdi Haghshenas (U. Münster)

Title: Boundedness and energy estimates for wave equation on various spacetimes

Abstract: We will discuss the derivation of robust energy estimates, including energy boundedness, integrated local energy decay, and r^p estimates, on Minkowski space, Schwarzschild black hole, and FLRW spacetimes. We will compare how these methods apply in each setting and identify the geometric features captured by each estimates.

20th October 2026: Chun-Kai Kevin Chien (U. Münster)

Title: On metric determination from minimal areas in higher codimension

Abstract: Motivated by Riemannian minimal area rigidity in three dimensional manifolds foliated by minimal surfaces and the AdS/CFT correspondence in physics, we talk about forthcoming work in the analogous setting of two-dimensional minimal surfaces in Riemannian manifolds of dimension higher than three. This features joint work with Tracey Balehowsky, Matti Lassas, and Tony Liimatainen.

27th October 2026: Chun-Kai Kevin Chien (U. Münster)

Title: On metric determination from minimal areas in higher codimension

Abstract: We continue the previous talk.

3rd November 2026: Lamberto Tresoldi (École Polytechnique)

Title: Nonlinear stability of Schwarzschild black holes for the Einstein–massless Dirac system in spherical symmetry

Abstract: We will discuss the nonlinear stability of Schwarzschild black holes for the Einstein–massless Dirac system under spherical symmetry. In particular, we will explore how standard techniques, such as energy estimates and bootstrap arguments, can be adapted to a setting in which the matter field is more deeply coupled to the geometry than in the corresponding Einstein–scalar field system, and the energy-momentum tensor does not satisfy the positive energy condition.

10th November 2026: Mónica Tapia del Moral (U. Cambridge)

Title: Gravitational collapse to extremal black holes with Λ > 0

Abstract: Extremal black holes have long been regarded as unphysical objects that cannot arise via gravitational collapse in physically plausible scenarios. In the asymptotically flat setting, this paradigm was overturned by Kehle and Unger, who used characteristic gluing to construct regular, spherically symmetric solutions to the Einstein–Maxwell-charged scalar field system that collapse to form an exactly extremal Reissner–Nordström black hole in finite time. In this talk, we explore how these techniques can be extended to include a positive cosmological constant, yielding solutions to the Einstein-scalar field system in which an exactly extremal Schwarzschild–de Sitter black hole is formed. We also discuss the dynamical formation of the related extremal Schwarzschild–de Sitter white hole and Nariai spacetimes.

17th November 2026: Milos Provci (U. Münster)

Title: Dissipative boundary conditions for the Teukolsky equation in AdS and Schwarzschild-AdS

Abstract: I will present a linear stability result for Schwarzschild-Anti-de Sitter under the assumption of suitably motivated boundary conditions for the linearized system of gravitational perturbations. We will see a juxtaposition with other, equally admissible, boundary conditions on pure Anti-de Sitter, and discuss obstructions in the black hole case.

1st December 2026: Maurice Schmit (ETH Zurich)

Title: The formation of trapped surfaces for the spherically symmetric Einstein-KleinGordon system

Abstract: We will discuss the formation of trapped surfaces for the Einstein-KleinGordon system in spherical symmetry. We will start by deriving the evolution and constraint equations in double-null coordinates for this system. Specifying initial data on the initial null hypersurfaces then leads to the characteristic initial value problem (CIVP). We will then briefly discuss two existence results for the CIVP before investigating the formation of a trapped surface by adapting Christodoulou’s short pulse ansatz.