A new partial geometry pg(5,5,2)

Abstract

We construct a new partial geometry with parameters pg(5, 5, 2), not isomorphic to the partial geometry of van Lint and Schrijver.2000 Mathematics Subject Classification. 51E14.

Switching for Small Strongly Regular Graphs

“…The point graph of this partial geometry is an SRG with parameters (81, 30, 9, 12). Recently, a second partial geometry of the same type was discovered by Krčadinac[19] and, almost at the same time, by Crnković, Švob and Tonchev[8]. More details on V NO − (4, 2) can be found in [4, §10.29].We can describe the SRG derived from the vL-S geometry as follows.…”