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Systèmes linéaires adjoints L 2

Philippe Eyssidieux (1999)

Annales de l'institut Fourier

Nous développons une version de la théorie d’indice L 2 d’Atiyah pour les faisceaux cohérents sur les variétés algébriques lisses et l’utilisons pour attaquer certaines questions de J. Kollár.Soit X une variété complexe compacte projective algébrique lisse et connexe. Nous prouvons que si L est un diviseur nef et gros, tel que la restriction de K X + L à la fibre générale d’une application de Shafarevich est effective, K X + L est effectif.Soit X une variété kählérienne compacte telle qu’il existe une classe...

Teorema de irreducibilidad para correspondencias algebraicas.

Eugenio Roanes (1980)

Revista Matemática Hispanoamericana

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 automorphism group of M ¯ 0 , n

Andrea Bruno, Massimiliano Mella (2013)

Journal of the European Mathematical Society

The paper studies fiber type morphisms between moduli spaces of pointed rational curves. Via Kapranov’s description we are able to prove that the only such morphisms are forgetful maps. This allows us to show that the automorphism group of M ¯ 0 , n is the permutation group on n elements as soon as n 5 .

The automorphism groups of Zariski open affine subsets of the affine plane

Zbigniew Jelonek (1994)

Annales Polonici Mathematici

We study some properties of the affine plane. First we describe the set of fixed points of a polynomial automorphism of ℂ². Next we classify completely so-called identity sets for polynomial automorphisms of ℂ². Finally, we show that a sufficiently general Zariski open affine subset of the affine plane has a finite group of automorphisms.

The Bogomolov multiplier of groups of order p 7 and exponent p

Zeinab Araghi Rostami, Mohsen Parvizi, Peyman Niroomand (2024)

Czechoslovak Mathematical Journal

We conduct an in-depth investigation into the structure of the Bogomolov multiplier for groups of order p 7 ( p > 2 ) and exponent p . We present a comprehensive...

The effect of rational maps on polynomial maps

Pierrette Cassou-Noguès (2001)

Annales Polonici Mathematici

We describe the polynomials P ∈ ℂ[x,y] such that P ( 1 / v , A v + A v 2 n + . . . + A m - 1 v n ( m - 1 ) + v n m - k w ) [ v , w ] . As applications we give new examples of bad field generators and examples of families of polynomials with smooth and irreducible fibers.

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