Spectral rigidity of Fuchsian groups of small signature
Peter Buser
Ecole Polytechnique Federale de Lausanne
Wednesday, April 3
2:30-3:30 pm, Room 4422
The lecture is about the so-called inverse spectral geometry
in the domain of Fuchsian groups, or what is the same,
Riemann surfaces endowed with a hyperbolic metric.
It is well known that two Fuchsian groups of a given signature
(g,m) have the same spectrum of the Laplacian if and only if
they have the same spectrum of the traces of the elements of the group
(trace spectrum). The general question is, to what extent does either
spectrum
determine the group.
For signatures not too small (e.g. all signatures (g, 0) with g >3),
isospectral
non conjugate examples are known. The lecture will be about methods
proving
that in the case of small signatures the group is entirely determined by
the spectrum.