On second fundamental forms of projective varieties.
On seminormal schemes
On set theoretic complete intersections in IP3.
On set theoretic complete intersections in IP3 (Erratum).
On set theoretic complete intersections in P3k.
On simple germs with non-isolated singularities.
On Singular Complex Surfaces with Negative Canonical Bundle, with Applications to Singular Compactifications of C2 and to 3-Dimensional Rational Singularities.
On singularities arising from the contraction of the minimal section a a ruled surface.
On SL(2)-actions without 3-dimensional orbits
On smooth surfaces in Gr(1, P3) with a fundamental curve.
On Some Arithmetic Properties of Odd Dimensional Complete Intersections
On some generalizations of Jacobi's residue formula
On some geometric aspects of Bruhat orderings. I. A finer decomposition of Bruhat cells.
On some numerical properties of Fano varieties
This is the text of a talk given at the XVII Convegno dellUnione Matematica Italiana held at Milano, September 8-13, 2003. I would like to thank Angelo Lopez and Ciro Ciliberto for the kind invitation to the conference. I survey some numerical conjectures and theorems concerning relations between the index, the pseudo-index and the Picard number of a Fano variety. The results I refer to are contained in the paper [3], wrote in collaboration with Bonavero, Debarre and Druel.
On some properties of partial intersection schemes.
Partial intersection subschemes of Pr of codimension c were used to furnish various graded Betti numbers which agree with a fixed Hilbert function. Here we study some further properties of such schemes; in particular, we show that they are not in general licci and we give a large class of them which are licci. Moreover, we show that all partial intersections are glicci. We also show that for partial intersections the first and the last Betti numbers, say m and p respectively, give bounds each other;...
On special projections of varieties: Epitome to a theorem of Beniamino Segre.
On spherical nilpotent orbits and beyond
We continue investigations that are concerned with the complexity of nilpotent orbits in semisimple Lie algebras. We give a characterization of the spherical nilpotent orbits in terms of minimal Levi subalgebras intersecting them. This provides a kind of canonical form for such orbits. A description minimal non-spherical orbits in all simple Lie algebras is obtained. The theory developed for the adjoint representation is then extended to Vinberg’s -groups. This yields a description of spherical...
On spinor varieties and their secants.
On sums of algebraic surfaces.
On symmetric semialgebraic sets and orbit spaces
For a symmetric (= invariant under the action of a compact Lie group G) semialgebraic basic set C, described by s polynomial inequalities, we show, that C can also be written by s + 1 G-invariant polynomials. We also describe orbit spaces for the action of G by a number of inequalities only depending on the structure of G.