A four-class association scheme derived from a hyperbolic quadric in PG(3,q)
نویسنده
چکیده
We prove the existence of a four-class association scheme on the set of external lines with respect to a hyperbolic quadric of PGð3; qÞ where qd 4 is a power of 2. This result is an analogue of the one by Ebert, Egner, Hollmann and Xiang. Taking a quotient of this association scheme yields a strongly regular graph of Latin square type. We show that this strongly regular graph can also be obtained by a generalization of the construction given by Mathon.
منابع مشابه
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The group PGL(2, q) has an embedding into PGL(3, q) such that it acts as the group fixing a nonsingular conic in PG(2, q). This action affords a coherent configuration R(q) on the set L(q) of non-tangent lines of the conic. We show that the relations can be described by using the cross-ratio. Our results imply that the restrictions R+(q) and R−(q) of R(q) to the set L+(q) of secant (hyperbolic)...
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تاریخ انتشار 2003