Alternatively have a look at the program.

## Transformation of surfaces and their applications to spectral theory

## Isometric Circle Actions on Positively Curved 4-Manifolds

## Entropy-rigidity of convex cocompact manifolds

## Triangulation and volume form on moduli space of flat surfaces

## Reeb dynamics, holomorphic discs, and the 4-ball

This is joint work with Hansjörg Geiges. Extending our work on Cerf's theorem we apply our moduli-theoretic version of Eliashberg-Hofer's filling-with-holomorphic-discs method to symplectic manifolds with cylindrical ends. Is the tight 3-sphere one of its positive ends we obtain existence results for contractible closed Reeb orbits, filling obstructions, and non-existence results for Liouville cobordisms.

## Stochastic completeness and volume growth

## Spectrally rigid subsets of free groups

## Generating pairs of solvable groups

Any two basis of a finite dimensional vector space are related by a finite sequence of moves, namely the elementary moves of the Gauss elimination process. Nielsen transfomations are group-theoretic analogs of Gauss's moves. A group may however possess unrelated generating n-tuples. Considering the case n=2, I will explain how to compute a complete set of invariants for the induced Nielsen equivalence relation in a class of abelian-by-cyclic groups.

## On Teichmuller spaces for surfaces of infinite type

Teichmuller spaces for surfaces of infinite type can be studied with geometric techniques, like the pair of pants decomposition and and Fenchel-Nielsen coordinates. In this case we have countably infinitely many pairs-of-pants and coordinates. With these techniques we can describe, under certain hypotheses, the topology given by the Teichmuller distance and the topology given by the "length spectrum" distance.

## Infinitesimal rigidity of surfaces and manifolds and the Hilbert-Einstein functional

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