Automorphism groups of primitive distance-bitransitive graphs are almost simple

We apply a result of Praeger, Saxl and Yokoyama [4] concerning the automorphism groups of primitive distance-transitive graphs to primitive distance-bitransitive graphs. Imprimitive distance-bitransitive graphs are discussed in Section 2. One of the cases of the Praeger, Saxl and Yokayama Theorem is considered in Section 3 and the following main result is proved in Section 4.