On the Fundamental Group of the Space of Cubic Surfaces.
Pre-Tango structures and uniruled varieties
The pre-Tango structure is an ample invertible sheaf of locally exact differentials on a variety of positive characteristic. It is well known that pre-Tango structures on curves often induce pathological uniruled surfaces. We show that almost all pre-Tango structures on varieties induce higher-dimensional pathological uniruled varieties, and that each of these uniruled varieties also has a pre-Tango structure. For this purpose, we first consider the p-closed rational vector field induced...
Projective subspaces in the variety of normal sections and tangent spaces to a symmetric space.
Segre-Veronese embeddings of P1 x P1 x P1 and their secant varieties.
In this paper we compute the dimension of all the sth higher secant varieties of the Segre-Veronese embeddings Yd of the product P1 × P1 × P1 in the projective space PN via divisors of multidegree d = (a,b,c) (N = (a+1)(b+1)(c+1) - 1). We find that Yd has no deficient higher secant varieties, unless d = (2,2,2) and s = 7, or d = (2h,1,1) and s = 2h + 1, with defect 1 in both cases.
Smooth lines on projective planes over two-dimensional algebras and submanifolds with degenerate Gauss maps.
Some Criteria for Rigidity of Noetherian Rings.
Spherical Complexes and Nonprojective Tone Varieties.
Tate duality and wild ramification.
The decomposition and specialization of algebraic families of vector bundles
Variétés unirationnelles non rationnelles
Varieties of modules over tubular algebras
We classify the irreducible components of varieties of modules over tubular algebras. Our results are stated in terms of root combinatorics. They can be applied to understand the varieties of modules over the preprojective algebras of Dynkin type 𝔸₅ and 𝔻₄.
Zur Homologie projektiv algebraischer Varietäten
О внутренних геометриях многообразия нуль- плоскостей максимальной размерности поляритетов второго порядка