Mathematical Research Letters

Volume 18 (2011)

Number 4

A Remark on Zak’s Theorem on Tangencies

Pages: 783 – 789

DOI: http://dx.doi.org/10.4310/MRL.2011.v18.n4.a15

Author

José Carlos Sierra (Instituto de Ciencias Matemáticas (ICMAT))

Abstract

We present a slightly different formulation of Zak’s theorem on tangencies as well as some applications. In particular, we obtain a better bound on the dimension of the dual variety of a manifold and we classify extremal and next-to-extremal cases when its secant variety does not fill up the ambient projective space.

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