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Deformations and the koherence

Markl, Martin (1994)

Proceedings of the Winter School "Geometry and Physics"

The cotangent cohomology of S. Lichtenbaum and M. Schlessinger [Trans. Am. Math. Soc. 128, 41-70 (1967; Zbl 0156.27201)] is known for its ability to control the deformation of the structure of a commutative algebra. Considering algebras in the wider sense to include coalgebras, bialgebras and similar algebraic structures such as the Drinfel’d algebras encountered in the theory of quantum groups, one can model such objects as models for an algebraic theory much in the sense of F. W. Lawvere [Proc....

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...

Déformations de flots d'Anosov et de groupes fuchsiens

Étienne Ghys (1992)

Annales de l'institut Fourier

Nous étudions les flots d’Anosov sur les variétés compactes de dimension 3 pour lesquels les distributions stable et instable faibles sont de classe C . Nous classons tous ces flots lorsqu’ils préservent le volume puis nous construisons une famille d’exemples qui ne préservent pas le volume. Nous classons aussi ces flots sous une hypothèse de “pincement”. En application, nous décrivons les déformations des groupes fuchsiens dans le groupe des difféomorphismes du cercle.

Deformations of Batalin-Vilkovisky algebras

Olga Kravchenko (2000)

Banach Center Publications

We show that a graded commutative algebra A with any square zero odd differential operator is a natural generalization of a Batalin-Vilkovisky algebra. While such an operator of order 2 defines a Gerstenhaber (Lie) algebra structure on A, an operator of an order higher than 2 (Koszul-Akman definition) leads to the structure of a strongly homotopy Lie algebra ( L -algebra) on A. This allows us to give a definition of a Batalin-Vilkovisky algebra up to homotopy. We also make a conjecture which is a...

Deformations of Lie brackets: cohomological aspects

Marius Crainic, Ieke Moerdijk (2008)

Journal of the European Mathematical Society

We introduce a new cohomology for Lie algebroids, and prove that it provides a differential graded Lie algebra which “controls” deformations of the structure bracket of the algebroid.

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...

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