Algebraic Graph Theory Seminar - Roman Nedela (22.11.2019)

Friday 22.11.2019 at 13:30, Lecture room XI

20. 11. 2019 21.29 hod.
By: Martin Mačaj

Roman Nedela (University of West Bohemia):
Recursive characterisations of automorphisms groups of some classes of graphs

Abstract:
R. Frucht proved that every finite abstract group is isomorphic to the automorphism group of a finite graph. There are some other classes of graphs that are universal in the above sense. On the other hand side, there are some natural classes of graphs like trees, interval graphs, or planar graphs, for which the structure of their groups of symmetries is restricted. We will discuss the problem how to describe the abstract groups that are realised as groups of automorphisms of particular families of graphs. A general method will be demonstrated on trees and planar graphs. A new concept of inhomogeneous wreath product turns to be essential.