Quadratic Embedding Constants of Strongly Regular Graphs

Abstract

We obtain an explicit formula for the quadratic embedding constant (QEC) of a strongly regular graph $\mathrm{srg}(n,k,\hat{I}»,\hat{I}¼)$ with $\hat{I}¼\ge 1$. By using QEC we give a necessary and sufficient condition for a strongly regular graph to admit a quadratic embeddingin a Euclidean space.