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3-folds of general type with K 3 = 4 ⁢ p g - 14

Paola Supino (1999)

Bollettino dell'Unione Matematica Italiana

In questo lavoro vengono costruite famiglie di 3-folds algebriche e non singolari X di tipo generale tali che l'invariante K X 3 sia il minimo possibile rispetto al genere geometrico p g , quando si suppone che il morfismo canonico sia birazionale. Per tali 3-folds vale la relazione lineare K X 3 = 4 ⁢ p g - 14 inoltre l'immagine del morfismo canonico é una varietà di Castelnuovo di P p g - 1 .

A 4₃ configuration of lines and conics in ℙ⁵

Tomasz Szemberg (1994)

Annales Polonici Mathematici

Studying the connection between the title configuration and Kummer surfaces we write explicit quadratic equations for the latter. The main results are presented in Theorems 8 and 16.

Asymptotic behaviour of numerical invariants of algebraic varieties

F. L. Zak (2012)

Journal of the European Mathematical Society

We show that if the degree of a nonsingular projective variety is high enough, maximization of any of the most important numerical invariants, such as class, Betti number, and any of the Chern or middle Hodge numbers, leads to the same class of extremal varieties. Moreover, asymptotically (say, for varieties whose total Betti number is big enough) the ratio of any two of these invariants tends to a well-defined constant.

Classes de cohomologie positives dans les variétés kählériennes compactes

Olivier Debarre (2004/2005)

Séminaire Bourbaki

Étant donnée une variété kählérienne compacte X , on étudie dans l’espace vectoriel réel de cohomologie de Dolbeault H 1 , 1 ( X , 𝐑 ) ⊂ H 2 ( X , 𝐑 ) le cône convexe des classes de Kähler ainsi que celui, plus grand, des classes de courants positifs fermés de type ( 1 , 1 ) . Lorsque X est projective, les traces de ces cônes sur l’espace de Néron–Severi NS ( X ) 𝐑 ⊂ H 1 , 1 ( X , 𝐑 ) engendré par les classes entières sont respectivement le cône des classes de diviseurs amples et l’adhérence de celui des classes de diviseurs effectifs.

Equivalence problem for minimal rational curves with isotrivial varieties of minimal rational tangents

Jun-Muk Hwang (2010)

Annales scientifiques de l'École Normale Supérieure

We formulate the equivalence problem, in the sense of É. Cartan, for families of minimal rational curves on uniruled projective manifolds. An important invariant of this equivalence problem is the variety of minimal rational tangents. We study the case when varieties of minimal rational tangents at general points form an isotrivial family. The main question in this case is for which projective variety Z , a family of minimal rational curves with Z -isotrivial varieties of minimal rational tangents...

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