We shall introduce and study quadratic entry locus varieties, a class of projective algebraic varieties whose extrinsic and intrinsic geometry is very rich. Let us recall that, for an irreducible non-degenerate variety X ⊂ P of dimension n ≥ 1, the secant defect of X , denoted by δ(X), is the difference between the expected dimension and the effective… (More)

KEBEKUS, Geometry of chains of minimal rational curves

S.J.M. HWANG

J. Reine Angew. Math

2005

Prolongations of infinitesimal linear automorphisms of projective varieties and rigidity of rational homogeneous spaces of Picard number 1 under Kähler deformation