c-Extensions of the F4(2)-building
Ivanov, A. A.
Pasechnik, Dmitrii V.
Date of Issue2002
School of Physical and Mathematical Sciences
We construct four geometries ε1,..., ε4 with the diagram such that any two elements of type 1 are incident to at most one common element of type 2 and three elements of type 1 are pairwise incident to common elements of type 2 if and only if they are incident to a common element of type 5. The automorphism group Ei of εi is flag-transitive, isomorphic to 2E6(2): 2,3.2 E6(2) :2,226: F4(2) and E6(2) : 2, for i=1,2,3 and 4. We calculate the suborbit diagram of the collinearity graph of εi with respect to the action of Ei. By considering the elements in εi fixed by a subgroup Ti of order 3 in Ei we obtain four geometries T1,...,T4 with the diagram on which CEi(Ti) induces flag-transitive action, isomorphic to U6(2): 2,3. U6(2): 2, 214: Sp6(2) and L6(2): 2 for i=1,2,3 and 4. Next, by considering the elements fixed by a subgroup Si of order 7 in Ei we obtain four geometries with the diagram on which CEi(Si) induces flag-transitive action isomorphic to L3(4): 2, 3.L3(4): 2, 28: L3(2) and (L3(2)xL3(2)): 2, for i=1,2,3 and 4.
DRNTU::Science::Mathematics::Discrete mathematics::Theory of computation
© 2002 Elsevier Science B.V. This is the author created version of a work that has been peer reviewed and accepted for publication by Discrete Mathematics, Elsevier Science B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: DOI [http://dx.doi.org/10.1016/S0012-365X(02)00554-X].