TY - JOUR

T1 - Symmetric diameter two graphs with affine-type vertex-quasiprimitive automorphism group

AU - Amarra, C.

AU - Giudici, Michael

AU - Praeger, Cheryl

PY - 2013

Y1 - 2013

N2 - We study the class of G-symmetric graphs Γ with diameter 2, where G is an affine-type quasiprimitive group on the vertex set of Γ. These graphs arise from normal quotient analysis as basic graphs in the class of symmetric diameter 2 graphs. It is known that G = V × G0, where V is a finite-dimensional vector space over a finite field and G 0 is an irreducible subgroup of GL (V), and Γ is a Cayley graph on V. In particular, we consider the case where V = Fd p for some prime p and G 0 is maximal in GL (d, p), with G 0 belonging to the Aschbacher classes C2, C4, C6, C7 and C8. For G0 ε C6, C 7, we determine all diameter 2 graphs which arise. For G0 ε C6 we obtain necessary conditions for diameter 2, which restrict the number of unresolved cases to be investigated, and in some special cases determine all diameter 2 graphs. © 2012 Springer Science+Business Media, LLC.

AB - We study the class of G-symmetric graphs Γ with diameter 2, where G is an affine-type quasiprimitive group on the vertex set of Γ. These graphs arise from normal quotient analysis as basic graphs in the class of symmetric diameter 2 graphs. It is known that G = V × G0, where V is a finite-dimensional vector space over a finite field and G 0 is an irreducible subgroup of GL (V), and Γ is a Cayley graph on V. In particular, we consider the case where V = Fd p for some prime p and G 0 is maximal in GL (d, p), with G 0 belonging to the Aschbacher classes C2, C4, C6, C7 and C8. For G0 ε C6, C 7, we determine all diameter 2 graphs which arise. For G0 ε C6 we obtain necessary conditions for diameter 2, which restrict the number of unresolved cases to be investigated, and in some special cases determine all diameter 2 graphs. © 2012 Springer Science+Business Media, LLC.

U2 - 10.1007/s10623-012-9644-z

DO - 10.1007/s10623-012-9644-z

M3 - Article

VL - 68

SP - 127

EP - 139

JO - Designs Codes and Cryptography

JF - Designs Codes and Cryptography

SN - 0925-1022

IS - 1-3

ER -