Mathematical Research Letters
Volume 18 (2011)
A Remark on Zak’s Theorem on Tangencies
Pages: 783 – 789
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.