## ALGEBRA SEMINAR

“Wells' sequence for group extensions, Part II”

### by

SEMRA KAPTANOÐLU

(METU)

Abstract: For an extension $G$ of a group $Q$ by another group $N$ together with a coupling $\chi$, a homomorphism from $Q$ to the group of automorphisms of $N$, there is an exact sequence due to Charles Wells,  involving derivations from $Q$ to the center of $N$, automorphisms of  $G$ which restrict to automorphisms of $N$, compatible automorphism  pairs coming from the automorphisms of $N$ and $Q$, and $H2(Q, Z(N)$. Construction of the Wells' sequence and some applications of the sequence will be given.

Date : December 7, 2009 (Monday)

Time : 14:40-15:30

Place: Seminar Room SA-141