In fact, all (seven) known primitive triangle-free strongly regular graphs are actual *subgraphs* of the Higman-Sims graph (which btw was first constructed by Dale Mesner). A Moore graph of degree 57 would of course break this mold.

## Higman-Sims Graph

In fact, all (seven) known primitive triangle-free strongly regular graphs are actual *subgraphs* of the Higman-Sims graph (which btw was first constructed by Dale Mesner). A Moore graph of degree 57 would of course break this mold.