Abstract

Let G be a non-bipartite strongly regular graph on n vertices of valency k. We prove that if G has a distance-regular antipodal cover of diameter 4, then k≤ ⌊2(n+ 1)/5⌋, unless G is the complement of triangular graph T(7), the folded Johnson graph J(8, 4) or the folded halved 8-cube. However, for these three graphs the bound k≤ ⌊(n− 1)/2⌋ holds. This result implies that only one of a complementary pair of strongly regular graphs can be the antipodal quotient of an antipodal distance-regular graph.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.