On automorphisms of strongly regular graphs with λ=0, μ=2

The structure of fixed-point subgraphs of automorphisms of order 3 of strongly regular graphs with parameters (v,k,0, 2) is determined. Let G be the automorphism group of a hypothetical strongly regular graph with parameters (352, 26, 0, 2). Possible orders are found and the structure of fixed-point subgraphs is determined for elements of prime order in G. The four-subgroups of G are classified and the possible structure of the group G is determined. A strengthening of a result of Nakagawa on the automorphism groups of strongly regular graphs with λ=0, μ=2 is obtained.