Subconstituents of the orthogonal graph of type (m,m − 1,0) of odd characteristic

In this paper, the orthogonal graph of type (m,m−1,0) over Fq of odd characteristic is introduced. We study the elementary properties of the graph and show that the first subconstituent of it is a generalized strongly regular graph. Moreover, the structure of the second subconstituent and the adjacency relations between different subconstituents are given.