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Diffeomorphisms conformal on distributions

Kamil Niedziałomski (2009)

Annales Polonici Mathematici

Let f:M → N be a local diffeomorphism between Riemannian manifolds. We define the eigenvalues of f to be the eigenvalues of the self-adjoint, positive definite operator df*df:TM → TM, where df* denotes the operator adjoint to df. We show that if f is conformal on a distribution D, then d i m V λ ≥ 2 d i m D - d i m M , where V λ denotes the eigenspace corresponding to the coefficient of conformality λ of f. Moreover, if f has distinct eigenvalues, then there is locally a distribution D such that f is conformal on D if and only...

Distributions involutives singulières

Dominique Cerveau (1979)

Annales de l'institut Fourier

On étudie les distributions involutives, i.e. les modules D de champs de vecteurs stables par le crochet de Lie, au voisinage d’un point 0 singulier. Après s’être ramené au cas purement singulier, c’est-à-dire où tous les éléments de D s’annulent en 0, des hypothèses génériques portant sur la partie linéaire de D nous permettent d’obtenir la linéarisation.

Double vector spaces

Alena Vanžurová (1987)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

Feuilletages holomorphes de codimension un dont la classe canonique est triviale

Frédéric Touzet (2008)

Annales scientifiques de l'École Normale Supérieure

We give a description of Kähler manifolds M equipped with an integrable subbundle ℱ of T M of rank n - 1 ( n = dim M ) under the assumption that the line bundle D é t ℱ is numerically trivial. This is a sort of foliated version of Bogomolov’s theorem concerning Kähler manifolds with trivial canonical class.

Generic one-step bracket-generating distributions of rank four

Chiara De Zanet (2015)

Archivum Mathematicum

We give a uniform, explicit description of the generic types of one–step bracket–generating distributions of rank four. A manifold carrying such a structure has dimension at least five and no higher than ten. For each of the generic types, we give a brief description of the resulting class of generic distributions and of geometries equivalent to them. For dimensions different from eight and nine, these are available in the literature. The remaining two cases are dealt with in my doctoral thesis.

Geometric classes of Goursat flags and the arithmetics of their encoding by small growth vectors

Piotr Mormul (2004)

Open Mathematics

Goursat distributions are subbundles, of codimension at least 2, in the tangent bundles to manifolds having the flag of consecutive Lie squares of ranks not depending on a point and growing-very slowly-always by 1. The length of a flag thus equals the corank of the underlying distribution. After the works of, among others, Bryant&Hsu (1993), Jean (1996), and Montgomery&Zhitomirskii (2001), the local behaviours of Goursat flags of any fixed length r≥2 are stratified into geometric classes...

Geometry of control-affine systems.

Clelland, Jeanne N., Moseley, Christopher G., Wilkens, George R. (2009)

SIGMA. Symmetry, Integrability and Geometry: Methods and Applications [electronic only]

Gradient horizontal de fonctions polynomiales

Si Tiep Dinh, Krzysztof Kurdyka, Patrice Orro (2009)

Annales de l’institut Fourier

Nous étudions les trajectoires du gradient sous-riemannien (appellé horizontal) de fonctions polynômes. Dans ce cadre l’inégalité de Łojasiewicz n’est pas valide et une trajectoire du gradient horizontal peut être de longueur infinie, et peut même s’accumuler sur une courbe fermée. Nous montrons que ces comportement sont exceptionnels ; et que, pour une fonction générique les trajectoires de son gradient horizontal ont des propriétés similaires au cas du gradient riemannien. Pour obtenir la finitude...

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