Automorphism groups of symmetric graphs of valency 3

The seven types of symmetric graph of valency 3 are described in a unified way in terms of generators and relations for their automorphism groups, and some relationships among the types are deduced. Also a number of new finite symmetric graphs are defined, solving the first three problems posed by Djokovic and Miller in [J. Combin. Theory Ser. B 29 (1980), 195–230].