Abstract
The Segre variety \({\mathcal{S}_{1,2}}\) in PG(5, 2) is a 21-set of points which is shown to have a cubic equation Q(x) = 0. If T(x, y, z) denotes the alternating trilinear form obtained by completely polarizing the cubic polynomial Q, then the associate U # of an r-flat \({U \subset {\rm PG}(5, 2)}\) is defined to be
and so is an s-flat for some s. Those lines L of PG(5, 2) which are singular, satisfying that is L # = PG(5.2), are shown to form a complete spread of 21 lines. For each r-flat \({U \subset {\rm PG}(5, 2)}\) its associate U # is determined. Examples are given of four kinds of planes P which are self-associate, P # = P, and three kinds of planes for which P, P #, P ## are disjoint planes such that P ### = P.
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Communicated by J.W.P. Hirschfeld.
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Shaw, R., Gordon, N.A. The cubic Segre variety in PG(5, 2). Des. Codes Cryptogr. 51, 141–156 (2009). https://doi.org/10.1007/s10623-008-9250-2
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DOI: https://doi.org/10.1007/s10623-008-9250-2
Keywords
- Cubic hypersurfaces in PG(n, 2)
- Associate of a projective flat
- Segre variety \({\mathcal{S}_{1,2}}\)
- Alternating trilinear form