On projective manifolds with nef anticanonical bundles.
On Projective Resolutions of Frobenius Algebras and Gorenstein Rings.
On projective toric varieties whose defining ideals have minimal generators of the highest degree
It is known that generators of ideals defining projective toric varieties of dimension embedded by global sections of normally generated line bundles have degree at most . We characterize projective toric varieties of dimension whose defining ideals must have elements of degree as generators.
On Projective Varieties of Codimension 2.
On projective varieties of minimal degree.
On proximity relations for valuations dominating a two-dimensional regular local ring.
The purpose of this paper is to define a new numerical invariant of valuations centered in a regular two-dimensional regular local ring. For this, we define a sequence of non-negative rational numbers δν = {δν(j)}j ≥ 0 which is determined by the proximity relations of the successive quadratic transformations at the points determined by a valuation ν. This sequence is characterized by seven combinatorial properties, so that any sequence of non-negative rational numbers having the above properties...
On Quadratic forms isotropic over the function field of a comic.
On quadrirational Yang-Baxter maps.
On quasihomogeneous manifolds – via Brion-Luna-Vust theorem
We consider a smooth projective variety on which a simple algebraic group acts with an open orbit. We discuss a theorem of Brion-Luna-Vust in order to relate the action of with the induced action of on the normal bundle of a closed orbit of the action. We get effective results in case and .
On quasi-periods of abelian functions with complex multiplication
On quasi-polarized manifolds whose sectional genus is equal to the irregularity
On quotients of complex surfaces under complex conjugation.
On radical-equivalent and zero-equivalent ideals
On ramification and genus of recursive towers.
On ramification locus of a polynomial mapping
Let X be a smooth algebraic hypersurface in ℂⁿ. There is a proper polynomial mapping F: ℂⁿ → ℂⁿ, such that the set of ramification values of F contains the hypersurface X.
On ramified covers of the projective plane II: Generalizing Segre’s theory
The classical Segre theory gives a necessary and sufficient condition for a plane curve to be a branch curve of a (generic) projection of a smooth surface in . We generalize this result for smooth surfaces in a projective space of any dimension in the following way: given two plane curves, and , we give a necessary and sufficient condition for to be the branch curve of a surface in and to be the image of the double curve of a -model of . In the classical Segre theory, a plane curve...
On Range Searching with Semialgebraic Sets.
On rank semistable vector bundles over an irreducible nodal curve of genus
Sia una curva irriducibile nodale di genere aritmetico . In queste note vogliamo mostrare come il sistema lineare delle quadriche, contenenti un opportuno modello proiettivo della curva, permette di descrivere i fibrati vettoriali semistabili, di rango , su .
On rank two vector bundles on an algebraic surface.
On ranks of Jacobian varieties in prime degree extensions
T. Dokchitser [Acta Arith. 126 (2007)] showed that given an elliptic curve E defined over a number field K then there are infinitely many degree 3 extensions L/K for which the rank of E(L) is larger than E(K). In the present paper we show that the same is true if we replace 3 by any prime number. This result follows from a more general result establishing a similar property for the Jacobian varieties associated with curves defined by an equation of the shape f(y) = g(x) where f and g are polynomials...