All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 6 Next

Displaying 101 – 120 of 356

Showing per page

Degree estimate for subalgebras generated by two elements

Leonid Makar-Limanov, Jie-Tai Yu (2008)

Journal of the European Mathematical Society

We develop a new combinatorial method to deal with a degree estimate for subalgebras generated by two elements in different environments. We obtain a lower bound for the degree of the elements in two-generated subalgebras of a free associative algebra over a field of zero characteristic. We also reproduce a somewhat refined degree estimate of Shestakov and Umirbaev for the polynomial algebra, which plays an essential role in the recent celebrated solution of the Nagata conjecture and the strong...

Degree of the fibres of an elliptic fibration

Alexandru Buium (1983)

Annales de l'institut Fourier

Let X → B an elliptic fibration with general fibre F . Let n e , n s , n a , n v be the minima of the non-zero intersection numbers ( ℒ , F ) where ℒ runs successively through the following sets: effective divisors on X , invertible sheaves spanned by global sections, ample divisors and very ample divisors. Let m be the maximum of the multiplicities of the fibres of X → B . We prove that n e = n s if and only if n e ≥ 2 m and that n a = n v if and only if n a ≥ 3 m .

Degree three cohomological invariants of semisimple groups

Alexander Merkurjev (2016)

Journal of the European Mathematical Society

We study the degree 3 cohomological invariants with coefficients in ℚ / ℤ ( 2 ) of a semisimple group over an arbitrary field. A list of all invariants of adjoint groups of inner type is given.

Degrés d’homogénéité de l’ensemble des intersections complètes singulières

Olivier Benoist (2012)

Annales de l’institut Fourier

Un résultat classique de Boole montre que, sur un corps de caractéristique 0, l’ensemble des hypersurfaces singulières de degré d dans ℙ N est un diviseur de degré ( N + 1 ) ( d - 1 ) N de l’espace projectif de toutes les hypersurfaces. On obtient ici des formules analogues pour des intersections complètes de codimension et de degrés quelconques dans ℙ N , en toute caractéristique.

Deligne-Lusztig restriction of a Gelfand-Graev module

Olivier Dudas (2009)

Annales scientifiques de l'École Normale Supérieure

Using Deodhar’s decomposition of a double Schubert cell, we study the regular representations of finite groups of Lie type arising in the cohomology of Deligne-Lusztig varieties associated to tori. We deduce that the Deligne-Lusztig restriction of a Gelfand-Graev module is a shifted Gelfand-Graev module.

Delta-composantes des espaces de modules de revêtements

Orlando Cau (2012)

Journal de Théorie des Nombres de Bordeaux

Nous nous intéressons aux composantes irréductibles des espaces de modules de G-revêtements et à leurs corps de définition. Nos résultats permettent de construire, quel que soit le groupe fini, de telles composantes définies sur ℚ . Notre méthode laisse de plus une grande latitude quant au type de ramification des revêtements. Ces composantes sont obtenues par déformation de certains revêtements du bord des espaces de modules. Enfin, ces composantes sont aussi compatibles dans une tour d’espaces...

Denominators of Igusa class polynomials

Kristin Lauter, Bianca Viray (2014)

Publications mathématiques de Besançon

In [22], the authors proved an explicit formula for the arithmetic intersection number CM ( K ) . G 1 on the Siegel moduli space of abelian surfaces, under some assumptions on the quartic CM field K . These intersection numbers allow one to compute the denominators of Igusa class polynomials, which has important applications to the construction of genus 2 curves for use in cryptography. One of the main tools in the proof was a previous result of the authors [21] generalizing the singular moduli formula of Gross...

Density of Morse functions on sets definable in o-minimal structures

Ta Lê Loi (2006)

Annales Polonici Mathematici

We present a tameness property of sets definable in o-minimal structures by showing that Morse functions on a definable closed set form a dense and open subset in the space of definable C p functions endowed with the Whitney topology.

Currently displaying 101 – 120 of 356