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On the group of real analytic diffeomorphisms

Takashi Tsuboi (2009)

Annales scientifiques de l'École Normale Supérieure

The group of real analytic diffeomorphisms of a real analytic manifold is a rich group. It is dense in the group of smooth diffeomorphisms. Herman showed that for the n -dimensional torus, its identity component is a simple group. For U ( 1 ) fibered manifolds, for manifolds admitting special semi-free U ( 1 ) actions and for 2- or 3-dimensional manifolds with nontrivial U ( 1 ) actions, we show that the identity component of the group of real analytic diffeomorphisms is a perfect group.

Small time-periodic solutions to a nonlinear equation of a vibrating string

Eduard Feireisl (1987)

Aplikace matematiky

In this paper, the system consisting of two nonlinear equations is studied. The former is hyperbolic with a dissipative term and the latter is elliptic. In a special case, the system reduces to the approximate model for the damped transversal vibrations of a string proposed by G. F. Carrier and R. Narasimha. Taking advantage of accelerated convergence methods, the existence of at least one time-periodic solution is stated on condition that the right-hand side of the system is sufficiently small.

Some quantitative results in singularity theory

Y. Yomdin (2005)

Annales Polonici Mathematici

The classical singularity theory deals with singularities of various mathematical objects: curves and surfaces, mappings, solutions of differential equations, etc. In particular, singularity theory treats the tasks of recognition, description and classification of singularities in each of these cases. In many applications of singularity theory it is important to sharpen its basic results, making them "quantitative", i.e. providing explicit and effectively computable estimates for all the important...

Time-periodic solutions of a quasilinear beam equation via accelerated convergence methods

Eduard Feireisl (1988)

Aplikace matematiky

The author investigates time-periodic solutions of the quasilinear beam equation with the help of accelerated convergence methods. Using the Newton iteration scheme, the problem is approximated by a sequence of linear equations solved via the Galerkin method. The derivatiove loss inherent to this kind of problems is compensated by taking advantage of smoothing operators.

Un teorema de extensión de Whitney en dimensión infinita y clase p.

Juan Margalef Roig, Enrique Outerelo Domínguez (1982)

Revista Matemática Hispanoamericana

Se prueba que si f es una aplicación de clase p en un abierto de un cuadrante de un espacio de Banach real, entonces en cada punto del abierto, f admite una extensión de clase p a un entorno global de dicho punto.Se utiliza este resultado para establecer un teorema de extensión de Whitney en un cuadrante de un espacio de Banach y un teorema de la función inversa en variedades con borde anguloso.

Un théorème de fonctions implicites. Applications

Francis Sergeraert (1973)

Annales de l'institut Fourier

On énonce un théorème de fonctions implicites du type de Nash-Moser, et on indique une application à l’étude des singularités de fonctions différentiables réelles (problème du déploiement universel de Thom).

Una variedad diferenciable de dimensión infinita, separada y no regular.

Juan Margalef Roig, Enrique Outerelo Domínguez (1982)

Revista Matemática Hispanoamericana

A partir de un espacio de Hilbert, E, de dimensión infinita separable y de un elemento λ de L(E,R) - {0} se construye un homeomorfismo h0 de(Eλ+ - Ker λ) U {0}sobre E con las topologías usuales tal que h0(0) = 0 y h0|Eλ+ - Ker λ es un difeomorfismo de clase ∞ de Eλ+ - Ker λ sobre E - {0}, con las estructuras diferenciables de clase ∞ usuales. Mediante h0 se construye una variedad diferenciable de dimensión infinita, separada y no regular.

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