We prove that the order of the vertex-stabiliser in an arc-transitive digraph of prime outvalence in bounded above by the third power of the number of vertices, with the exception of a well described family of digraphs, in which the growth of the vertex-stabiliser in exponential.
We classify all finite faithful amalgams of index (4,2) and use this result to construct all tetravalent 2-arc-transitive graphs with at most 512 vertices.
COBISS.SI-ID: 15134809