A characterization of projective subspaces of codimension two as quasi-symmetric designs with good blocks Original Research Article

In this paper we prove that any strongly regular graph with μ=1μ=1 satisfies k⩾(λ+1)(λ+2)k⩾(λ+1)(λ+2) and any strongly regular graph with μ=2μ=2 is either a grid graph or satisfies View the MathML sourcek⩾12λ(λ+3). This improves upon a previous result of Brouwer and Neumaier who gave a necessary restriction on the parameters of strongly regular graphs with μ=2μ=2 and View the MathML sourcek<12λ(λ+3).