Abstract
LetV ⊂ ℙℝn be an algebraic variety, such that its complexificationV ℂ ⊂ ℙn is irreducible of codimensionm ≥ 1. We use a sufficient condition on a linear spaceL ⊂ ℙℝn of dimensionm + 2r to have a nonempty intersection withV, to show that any six dimensional subspace of 5 × 5 real symmetric matrices contains a nonzero matrix of rank at most 3.
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Friedland, S., Libgober, A.S. Generalizations of the odd degree theorem and applications. Isr. J. Math. 136, 353–371 (2003). https://doi.org/10.1007/BF02807205
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DOI: https://doi.org/10.1007/BF02807205