For every hyperoval O of PG(2.q) (q even). we construct an extended generalized quadrangle with point-residues isomorphic to the generalized quadrangle T-2(*)(O) of order (q - I, q + l). These extended generalized quadrangles are Rag-transitive only when q = 2 or 4. When q = 2 we obtain a thin-lined polar space with four planes on every line. When q = 4 we obtain one of the geometries discovered by Yoshiara [28]. That geometry is produced in [28] as a quotient of another one. which is simply connected, constructed in [28] by amalgamation of parabolics. In this paper we also give a 'topological' construction of that simply connected geometry. (C) 1997 Academic Press Limited.

DEL FRA, A., Pasechnik, D., Pasini, A. (1997). A new family of extended generalized quadrangles. EUROPEAN JOURNAL OF COMBINATORICS, 18(2), 155-169 [10.1006/eujc.1995.0091].

A new family of extended generalized quadrangles

PASINI, ANTONIO
1997-01-01

Abstract

For every hyperoval O of PG(2.q) (q even). we construct an extended generalized quadrangle with point-residues isomorphic to the generalized quadrangle T-2(*)(O) of order (q - I, q + l). These extended generalized quadrangles are Rag-transitive only when q = 2 or 4. When q = 2 we obtain a thin-lined polar space with four planes on every line. When q = 4 we obtain one of the geometries discovered by Yoshiara [28]. That geometry is produced in [28] as a quotient of another one. which is simply connected, constructed in [28] by amalgamation of parabolics. In this paper we also give a 'topological' construction of that simply connected geometry. (C) 1997 Academic Press Limited.
1997
DEL FRA, A., Pasechnik, D., Pasini, A. (1997). A new family of extended generalized quadrangles. EUROPEAN JOURNAL OF COMBINATORICS, 18(2), 155-169 [10.1006/eujc.1995.0091].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/7078
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