scholarly journals Secant varieties of Segre–Veronese varieties

2012 ◽  
Vol 6 (8) ◽  
pp. 1817-1868 ◽  
Author(s):  
Claudiu Raicu
2007 ◽  
Vol 59 (3) ◽  
pp. 488-502 ◽  
Author(s):  
A. Bernardi ◽  
M. V. Catalisano ◽  
A. Gimigliano ◽  
M. Idà

AbstractWe consider the k-osculating varieties Ok,n.d to the (Veronese) d-uple embeddings of ℙn. We study the dimension of their higher secant varieties via inverse systems (apolarity). By associating certain 0-dimensional schemes Y ⊂ ℙn to and by studying their Hilbert functions, we are able, in several cases, to determine whether those secant varieties are defective or not.


2014 ◽  
Vol 57 (2) ◽  
pp. 401-413 ◽  
Author(s):  
WERONIKA BUCZYŃSKA ◽  
JAROSŁAW BUCZYŃSKI

AbstractWe consider higher secant varieties to Veronese varieties. Most points on the rth secant variety are represented by a finite scheme of length r contained in the Veronese variety – in fact, for a general point, the scheme is just a union of r distinct points. A modern way to phrase it is: the smoothable rank is equal to the border rank for most polynomials. This property is very useful for studying secant varieties, especially, whenever the smoothable rank is equal to the border rank for all points of the secant variety in question. In this note, we investigate those special points for which the smoothable rank is not equal to the border rank. In particular, we show an explicit example of a cubic in five variables with border rank 5 and smoothable rank 6. We also prove that all cubics in at most four variables have the smoothable rank equal to the border rank.


2008 ◽  
Vol 60 (5) ◽  
pp. 961-974 ◽  
Author(s):  
Silvia Abrescia

AbstractWe study the regularity of the higher secant varieties of ℙ1 × ℙn, embedded with divisors of type (d, 2) and (d, 3). We produce, for the highest defective cases, a “determinantal” equation of the secant variety. As a corollary, we prove that the Veronese triple embedding of ℙn is not Grassmann defective.


2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Carlos Amendola ◽  
Jean-Charles Faugere ◽  
Bernd Sturmfels

The points of a moment variety are the vectors of all moments up to some order, for a givenfamily of probability distributions. We study the moment varieties for mixtures of multivariate Gaussians.Following up on Pearson's classical work from 1894, we apply current tools from computational algebrato recover the parameters from the moments. Our moment varieties extend objects familiar to algebraicgeometers. For instance, the secant varieties of Veronese varieties are the loci obtained by setting allcovariance matrices to zero. We compute the ideals of the 5-dimensional moment varieties representingmixtures of two univariate Gaussians, and we oer a comparison to the maximum likelihood approach.


2011 ◽  
Vol 63 (3) ◽  
pp. 287-297 ◽  
Author(s):  
Hirotachi Abo ◽  
Maria Chiara Brambilla

2009 ◽  
Vol 18 (3) ◽  
pp. 369-384 ◽  
Author(s):  
Hirotachi Abo ◽  
Maria Chiara Brambilla

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