## 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.

### Appeal from Ukrainian mathematicians

The whole world witnessed how on February 24, the President of Russia Putin started a military invasion of Ukraine, which is a blatant act of…

## Next Activities

## Latest publications

#### Lipschitz rigidity for scalar curvature

Simone Cecchini, Bernhard Hanke, Thomas Schick

We prove the following Lipschitz rigidity result in scalar curvature geometry. Let $M$ be a closed smooth connected spin manifold of even dimension…

#### The relative index theorem for general first-order elliptic operators

Lashi Bandara

The relative index theorem is proved for general first-order elliptic operators that are complete and coercive at infinity over measured manifolds.…

#### Fundamental groups of split real Kac-Moody groups and generalized real flag manifolds. With appendices by Tobias Hartnick and Ralf Köhl and by Julius Grüning and Ralf Köhl

Paula Harring, Ralf Köhl

We determine the fundamental groups of symmetrizable algebraically simply connected split real Kac-Moody groups endowed with the Kac-Peterson…

#### Representations of Involutory Subalgebras of Affine Kac–Moody Algebras

Axel Kleinschmidt, Ralf Köhl, Robin Lautenbacher, Hermann Nicolai

We consider the subalgebras of split real, non-twisted affine Kac-Moody Lie algebras that are fixed by the Chevalley involution. These…

## Latest Blog posts

**Finite subgroups of homeomorphism groups**If \(M\) is a compact topological manifold, can one say something about its group of homeomorphisms \(\mathrm{Homeo}(M)\)? Of course one can, there is quite a lot to say about it, and there is also quite a lot which we still don’t know. Today I want to mention the following recent result by Csikós-Pyber-Szabó (arXiv:2204.13375): Let … Continue reading "Finite subgroups of homeomorphism groups"