## Combinatorics Seminar

When: Sunday, May 3, 10am
Where: Schreiber 309
Speaker: Andrzej Kisielewicz, Univ. of Wroclaw
Title:
Symmetries of graphs and other combinatorial structures
## Abstract:

It is known that every abstract group is isomorphic to the automorphism
group of some graph. It is also known that not every permutation group
is equal to the automorphism group of some graph. Describing those
permutation groups that are the automorphism groups of graphs is known
as a concrete version of the Konig problem. The problem is hard and open
in its generality.
We argue that it is the knowledge on the concrete automorphism groups that
is needed in many applications, and therefore the problem is important. We
present some results and some interesting questions motivated by the
general Konig problem. In particular we characterize graphs that (except
for the complete graphs and their complements) have the highest degree
of symmetry.