Seminar series
Date
Wed, 12 Jun 2013
Time
16:00 -
17:00
Location
SR1
Speaker
Benno Kuckuck
Organisation
University of Oxford
To any splitting of a group G as an HNN extension we can associate a
map from G to Z. Conversely, a group that allows a non-trivial
homomorphism to Z may be written as an HNN extension in an obvious way.
In this talk we will consider the question when
such a homomorphism G->Z is associated to a non-obvious HNN splitting
of G. We will then see how this information can be collected into an
invariant of the group which may be described by a simple connectivity
condition on Cayley graphs.