19-25 June 2011
Bled, Slovenia
Europe/Ljubljana timezone
On distance, geodesic and arc transitivity of graphs
Presented by Mr. WEI JIN
Type: Oral presentation
Track: Group Actions
Content
We compare three transitivity properties of finite graphs, namely,
for a positive integer $s$, $s$-distance transitivity, $s$-geodesic
transitivity and $s$-arc transitivity. It is known that if a finite
graph is $s$-arc transitive but not $(s+1)$-arc transitive then
$s\leq 7$ and $s\neq 6$. We show that there are infinitely many
geodesic transitive graphs with this property for each of these
values of $s$, and that these graphs can have arbitrarily large
diameter if and only if $1\leq s\leq 3$. Moreover, for a prime $p$
we prove that there exists a graph of valency $p$ that is 2-geodesic
transitive but not 2-arc transitive if and only if $p\equiv 1\pmod
4$, and for each such prime there is a unique graph with this
property: it is an antipodal double cover of the complete graph
$K_{p+1}$ and is geodesic transitive with automorphism group
$PSL(2,p)\times Z_2$.
Place
Location: Bled, Slovenia
Address: Best Western Hotel Kompas Bled
Primary authors
- Mr. WEI JIN The University of Western Australia
- Prof. Cheryl PRAEGER The University of Western Australia
- Prof. Cai Heng LI The University of Western Australia
- Dr. Alice DEVILLERS The University of Western Australia