The variety of polar simplices
Documenta mathematica, Tome 18 (2013), pp. 469-505
A collection of n distinct hyperplanes Li=li=0⊂Pn−1, the (n−1)-dimensional projective space over an algebraically closed field of characteristic not equal to 2, is a polar simplex of a smooth quadric Qn−2=q=0, if each Li is the polar hyperplane of the point pi=⋂j=iLj, equivalently, if q=l12+...+ln2 for suitable choices of the linear forms li. In this paper we study the closure VPS(Q,n)⊂Hilbn(Pˇn−1) of the variety of sums of powers presenting Q from a global viewpoint: VPS(Q,n) is a smooth Fano variety of index 2 and Picard number 1 when n6, and VPS(Q,n) is singular when n≥6.
Classification :
14J45
Mots-clés : quadric, Fano n-folds, polar simplex, syzygies
Mots-clés : quadric, Fano n-folds, polar simplex, syzygies
@article{10_4171_dm_406,
author = {Kristian Ranestad and Frank-Olaf Schreyer},
title = {The variety of polar simplices},
journal = {Documenta mathematica},
pages = {469--505},
year = {2013},
volume = {18},
doi = {10.4171/dm/406},
url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/406/}
}
Kristian Ranestad; Frank-Olaf Schreyer. The variety of polar simplices. Documenta mathematica, Tome 18 (2013), pp. 469-505. doi: 10.4171/dm/406
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