Leicester Pure Mathematics Seminar, 16/10/2008
4:30pm, MAB 119
Bernhard Koeck (University of Southampton)
Belyi's famous theorem states that a compact Riemann surface can be defined over a number field if and only if it admits a meromorphic function with at most three critical values. My talk will be about a generalization of this theorem to Klein surfaces, i.e. (possibly non-orientable) surfaces with boundary which carry a dianalytic structure. I will also explain some other characterizations (triangle groups, maps on surfaces, ...). The results presented are joint work with David Singerman on the one hand and with Eike Lau on the other hand.