Title: Embeddings of PSL_2(F_p) into semisimple linear algebraic groups.
Abstract: I will present the following theorem of Serre:
If G is a connected semisimple linear algebraic group over an
algebraically closed field k with trivial center and Coxeter number h
then
1) If p = h+1 is prime then G(k) contains a subgroup isomorphic to
PSL_2(F_p) unless the characteristic of k is 2 and G = PGL_2.
2) If p = 2h+1 then G(k) contains a subgroup isomorphic to PSL_2(F_p).