A new family of locally $5$-arc transitive graphs of pushing up type with respect to the prime 3

Abstract

Let $q$ be a power of the prime 3. A locally 5-arc transitive $G$-graph of pushing up type is constructed for each value of $q$. For $q=3$, the $G$-graph constructed provides an example of a graph with a vertex stabilizer amalgam of shape ${\cal E}_1$ in the sense of [1]. Whereas, for the other values of $q$, the vertex stabilizer amalgam of the $G$-graph is of a previously unknown shape. In particular, for $q \neq 3$, these graphs are the first examples of locally 5-arc transitive graphs containing a vertex $z$ for which the group that fixes all 3-arcs originating at $z$ is non-trivial.