## Welcome to SPP 2026

This is the platform of a coordinated research programme in mathematics, funded by the German Research Foundation (DFG). It comprises 80 research projects in the fields of differential geometry, geometric topology, and global analysis. More than 80 researchers from doctoral to professorial level and based at more than 20 German and Swiss universities are represented in this programme.

### SPP Conference 2025

The SPP Main Conference will take place from March 31 to April 4, 2025, at the MPI for Mathematics in the Sciences in Leipzig.

## Next Activities

## Latest publications

#### Hereditarily just-infinite torsion groups with positive first L2-Betti number

Steffen Kionke, Eduard Schesler

We present a new method to construct finitely generated, residually finite, infinite torsion groups. In contrast to known constructions, a profinite…

#### Realizing residually finite groups as subgroups of branch groups

Steffen Kionke, Eduard Schesler

We prove that every finitely generated, residually finite group G embeds into a finitely generated perfect branch group such that many properties of G…

#### Cohomogeneity one RCD-spaces

Diego Corro, Jaime Santos-Rodríguez, Jesús Núñez-Zimbrón

We study \(\mathsf{RCD}\)-spaces \((X,d,\mathfrak{m})\) with group actions by isometries preserving the reference measure \(\mathfrak{m}\) and whose…

#### On the Euler characteristic of S-arithmetic groups

Holger Kammeyer, Giada Serafini

We show that the sign of the Euler characteristic of an S-arithmetic subgroup of a simple k-group over a number field k depends on the S-congruence…