For a variety X of dimension n in P^r, r> n(k+1)+k-1, the k-th secant order of X is the number m_k(X) of (k+1)-secant k-spaces passing through a general point of the k-th secant variety. We show that, if r>n(k+1)+k, then m_k(X)=1 unless X is k--weakly defective. Furthermore we give a complete classification of surfaces X in P^r, r>3k+2, for which m_k(X)>1.

Chiantini, L., Ciliberto, C. (2006). On the concept of k-th secant order of a variety. JOURNAL OF THE LONDON MATHEMATICAL SOCIETY, 73(2), 436-454 [10.1112/S0024610706022630].

On the concept of k-th secant order of a variety

CHIANTINI, LUCA;
2006-01-01

Abstract

For a variety X of dimension n in P^r, r> n(k+1)+k-1, the k-th secant order of X is the number m_k(X) of (k+1)-secant k-spaces passing through a general point of the k-th secant variety. We show that, if r>n(k+1)+k, then m_k(X)=1 unless X is k--weakly defective. Furthermore we give a complete classification of surfaces X in P^r, r>3k+2, for which m_k(X)>1.
2006
Chiantini, L., Ciliberto, C. (2006). On the concept of k-th secant order of a variety. JOURNAL OF THE LONDON MATHEMATICAL SOCIETY, 73(2), 436-454 [10.1112/S0024610706022630].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/23790
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