Augmenting the Delsarte bound: a forbidden interval for the order of maximal cliques in strongly regular graphs

• Main Authors: Greaves, Gary Royden Watson, Koolen, Jack H., Park, Jongyook
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Mathematics; Delsarte Clique; Eigenvalue
• Online Access: https://hdl.handle.net/10356/159972
• Institution: Nanyang Technological University

In this paper, we study the order of a maximal clique in an amply regular graph with a fixed smallest eigenvalue by considering a vertex that is adjacent to some (but not all) vertices of the maximal clique. As a consequence, we show that if a strongly regular graph contains a Delsarte clique, then...