Secant cumulants and toric geometry

Abstract

We study the secant line variety of the Segre product of projective spaces using special cumulant coordinates adapted for secant varieties. We show that the secant variety is covered by open normal toric varieties. We prove that in cumulant coordinates its ideal is generated by binomial quadrics. We present new results on the local structure of the secant variety. In particular, we show that it has rational singularities and we give a description of the singular locus. We also classify all secant varieties that are Gorenstein. Moreover, generalizing (Sturmfels and Zwiernik 2012), we obtain analogous results for the tangential variety.

Some improvements to previous results, with other minor changes. Updated references

References in corpus (3)

• Tensor ranks on tangent developable of Segre varieties
• Constructive degree bounds for group-based models
• Equations for the third secant variety of the Segre product of n projective spaces

Cited by in corpus (7)

• Secants of minuscule and cominuscule minimal orbits
• Hyperdeterminants from the $E_8$ Discriminant
• Are all Secant Varieties of Segre Products Arithmetically Cohen-Macaulay?
• On singularities of third secant varieties of Veronese embeddings
• Flexible affine cones and flexible coverings
• When is a polynomial ideal binomial after an ambient automorphism?
• Selected topics on Toric Varieties