** "Geometry and Analysis on Groups" Research Seminar **

**Title:**
Residual p-finiteness and graphs of groups.

**Speaker:**
Gareth Wilkes (University of Cambridge)

**Abstract:**
A basic theorem of Serre states that the fundamental group of every finite graph of finite groups is residually finite. I will discuss the obstructions to extending this theorem to the case of residual p-finiteness of a graph of finte p-groups, and state and prove a theorem in this case, which is in fact applicable even to some infinite graphs of groups. I will then show how this theorem may be used to construct the first example of a finitely generated inaccessible group which is residually (p-)finite.