Surjectivity of Certain Injective Semialgebraic Transformations of IRn.
Teorema de irreducibilidad para correspondencias algebraicas.
Sea T una correspondencia algebraica irreducible entre dos variedades proyectivas, V y V', sobre un cuerpo k algebraicamente cerrado y de característica cero. Sea W una subvariedad irreducible de V y W' = T{W} la transformada total de W en T. En [1] se estudia el problema de la conexión de W' y en [3] se estudia el problema de la irreducibilidad de la transformada total de W en correspondencias locales. La finalidad de este artículo es la de aprovechar los resultados de los dos trabajos citados,...
The Birational Geometry of Surfaces with Rational Double Points.
The Cubo-Cubic Transformation of IP3 is Very Special.
The effect of rational maps on polynomial maps
We describe the polynomials P ∈ ℂ[x,y] such that . As applications we give new examples of bad field generators and examples of families of polynomials with smooth and irreducible fibers.
The exponent of an abelian subvariety.
The Extension of Regular and Rational Embeddings.
The field of definition for dynamical systems on
The Kähler cone on Calabi-Yau threefolds.
The Kähler cone on Calabi-Yau threefolds (Erratum).
The number of conjugacy classes of elements of the Cremona group of some given finite order
This note presents the study of the conjugacy classes of elements of some given finite order in the Cremona group of the plane. In particular, it is shown that the number of conjugacy classes is infinite if is even, or , and that it is equal to (respectively ) if (respectively if ) and to for all remaining odd orders. Some precise representative elements of the classes are given.
The set of points at which a polynomial map is not proper
We describe the set of points over which a dominant polynomial map is not a local analytic covering. We show that this set is either empty or it is a uniruled hypersurface of degree bounded by .
The Stable Adjunction Map on Gorenstein Varieties.
Theorems of factorizations for birational morphisms
Théorie différentielle du contact maximal en inégale caractéristique
Thom-Boardman singularities and monoidal transforms
Towards the classification of weak Fano threefolds with ρ = 2
In this paper, examples of type II Sarkisov links between smooth complex projective Fano threefolds with Picard number one are provided. To show examples of these links, we study smooth weak Fano threefolds X with Picard number two and with a divisorial extremal ray. We assume that the pluri-anticanonical morphism of X contracts only a finite number of curves. The numerical classification of these particular smooth weak Fano threefolds is completed and the geometric existence of some numerical cases...
Transversalité obtenue par éclatements permis
T-symmetrical tensor forms on complete intersections.
Two Reduction Theorems for Threefold Birational Morphisms.