2 research outputs found

    European Journal of Combinatorics Index, Volume 26

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    Eggs in PG(4n-1, q), q even, containing a pseudo-pointed conic

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    An ovoid of \PG(3,q) can be defined as a set of q2+1q^2+1 points with the property that every three points span a plane and at every point there is a unique tangent plane. In 2000 M. R. Brown (\cite{BROWN2000}) proved that if an ovoid of \PG(3,q), qq even, contains a pointed conic, then either q=4q=4 and the ovoid is an elliptic quadric, or q=8q=8 and the ovoid is a Tits ovoid. Generalising the definition of an ovoid to a set of (n−1)(n-1)-spaces of \PG(4n-1,q) J. A. Thas \cite{THAS1971} introduced the notion of pseudo-ovoids or eggs: a set of q2n+1q^{2n}+1 (n−1)(n-1)-spaces in \PG(4n-1,q), with the property that any three egg elements span a (3n−1)(3n-1)-space and at every egg element there is a unique tangent (3n−1)(3n-1)-space. We prove that an egg in \PG(4n-1,q), qq even, contains a pseudo pointed conic, that is, a pseudo-oval arising from a pointed conic of \PG(2,q^n), qq even, if and only if the egg is elementary and the ovoid is either an elliptic quadric in \PG(3,4) or a Tits ovoid in \PG(3,8)
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