Plane curves as projections of non singular space curves.
The “linear orbit” of a plane curve of degree is its orbit in under the natural action of . In this paper we compute the degree of the closure of the linear orbits of most curves with positive dimensional stabilizers. Our tool is a nonsingular variety dominating the orbit closure, which we construct by a blow-up sequence mirroring the sequence yielding an embedded resolution of the curve. The results given here will serve as an ingredient in the computation of the analogous information for...
A non-zero constant Jacobian polynomial map F=(P,Q):ℂ² → ℂ² has a polynomial inverse if the component P is a simple polynomial, i.e. its regular extension to a morphism p:X → ℙ¹ in a compactification X of ℂ² has the following property: the restriction of p to each irreducible component C of the compactification divisor D = X-ℂ² is of degree 0 or 1.
Let C be a smooth non-degenerate integral curve of degree d and genus g in over an algebraically closed field of characteristic zero. For each point P in let be the linear system on C induced by the hyperplanes through P. By one maps C onto a plane curve , such a map can be seen as a projection of C from P. If P is not the vertex of a cone of bisecant lines, then will have only finitely many singular points; or to put it slightly different: The secant scheme parametrizing divisors in...
In this paper we will prove that for a threefold of general type and large volume the second plurigenera is positive and the fifth canonical map is birational.
Le but de cette note est de donner une démonstration complète du théorème 4.1 de [5] qui a pour objet d’expliciter l’action de l’inertie modérée sur la semi-simplifiée modulo d’une certaine famille (assez restreinte) de représentations cristallines du groupe de Galois absolu d’un corps -adique . Lorsque n’est pas absolument ramifié, le calcul de cette action a déjà été accompli par Fontaine et Laffaille qui ont montré qu’elle est entièrement déterminée par les poids de Hodge-Tate de , au...