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Déformations d’algèbres associées à une variété symplectique (les * ν -produits)

André Lichnerowicz (1982)

Annales de l'institut Fourier

Fondements de la théorie des * v -produits. Notion de * v -produit de Vey; tout * v -produit est équivalent à un * v -produit de Vey. Sur toute variété symplectique paracompacte ( W , F ) telle que b 3 ( W ) = 0 , il existe des * v -produits de Vey. Caractérisation des algèbres de Lie engendrées par antisymétrisation d’un * v -produit (éventuellement faible); ce sont à une équivalence près, les algèbres de Lie de Vey.On considère les variétés symplectiques ( W , F ) sur lesquelles opère, par symplectomorphismes, un groupe de Lie G . Si ( W , F ) admet...

Deformations of Metrics and Biharmonic Maps

Aicha Benkartab, Ahmed Mohammed Cherif (2020)

Communications in Mathematics

We construct biharmonic non-harmonic maps between Riemannian manifolds ( M , g ) and ( N , h ) by first making the ansatz that ϕ : ( M , g ) → ( N , h ) be a harmonic map and then deforming the metric on N by h ˜ α = α h + ( 1 - α ) d f ⊗ d f to render ϕ biharmonic, where f is a smooth function with gradient of constant norm on ( N , h ) and α ∈ ( 0 , 1 ) . We construct new examples of biharmonic non-harmonic maps, and we characterize the biharmonicity of some curves on Riemannian manifolds.

Deformations of structures, embedding of a Riemannian manifold in a Kählerian one and geometric antigravitation

Alexander A. Ermolitski (2007)

Banach Center Publications

Tubular neighborhoods play an important role in modern differential topology. The main aim of the paper is to apply these constructions to geometry of structures on Riemannian manifolds. Deformations of tensor structures on a normal tubular neighborhood of a submanifold in a Riemannian manifold are considered in section 1. In section 2, this approach is used to obtain a Kählerian structure on the corresponding normal tubular neighborhood of the null section in the tangent bundle TM of a smooth manifold...

Deforming metrics of foliations

Vladimir Rovenski, Robert Wolak (2013)

Open Mathematics

Let M be a Riemannian manifold equipped with two complementary orthogonal distributions D and D ⊥. We introduce the conformal flow of the metric restricted to D with the speed proportional to the divergence of the mean curvature vector H, and study the question: When the metrics converge to one for which D enjoys a given geometric property, e.g., is harmonic, or totally geodesic? Our main observation is that this flow is equivalent to the heat flow of the 1-form dual to H, provided the initial 1-form...

Dégénerescence locale des transformations conformes pseudo-riemanniennes

Charles Frances (2012)

Annales de l’institut Fourier

Nous étudions l’ensemble Conf ( M , N ) des immersions conformes entre deux variétés pseudo-riemanniennes ( M , g ) et ( N , h ) . Nous caractérisons notamment l’adhérence de Conf ( M , N ) dans l’espace des applications continues 𝒞 0 ( M , N ) , et décrivons quelques propriétés géométriques de ( M , g ) lorsque cette adhérence est non triviale.

Density of a family of linear varietes

Grazia Raguso, Luigia Rella (2006)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

The measurability of the family, made up of the family of plane pairs and the family of lines in 3 -dimensional space A 3 , is stated and its density is given.

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