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Estimates in Besov spaces for transport and transport-diffusion equations with almost Lipschitz coefficients.

Raphaël Danchin (2005)

Revista Matemática Iberoamericana

This paper aims at giving an overview of estimates in general Besov spaces for the Cauchy problem on t = 0 related to the vector field ∂t + v·∇. The emphasis is on the conservation or loss of regularity for the initial data.When ∇u belongs to L1(0,T; L∞) (plus some convenient conditions depending on the functional space considered for the data), the initial regularity is preserved. On the other hand, if ∇v is slightly less regular (e.g. ∇v belogs to some limit space for which the embedding in L∞...

Estimates of solutions to linear elliptic systems and equations

Heinrich Begehr (1992)

Banach Center Publications

Whenever nonlinear problems have to be solved through approximation methods by solving related linear problems a priori estimates are very useful. In the following this kind of estimates are presented for a variety of equations related to generalized first order Beltrami systems in the plane and for second order elliptic equations in m . Different types of boundary value problems are considered. For Beltrami systems these are the Riemann-Hilbert, the Riemann and the Poincaré problem, while for elliptic...

Estimates of the derivatives for a class of parabolic degenerate operators with unbounded coefficients in N

Luca Lorenzi (2005)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

We consider a class of perturbations of the degenerate Ornstein-Uhlenbeck operator in N . Using a revised version of Bernstein’s method we provide several uniform estimates for the semigroup { T ( t ) } t 0 associated with the realization of the operator 𝒜 in the space of all the bounded and continuous functions in N

Estimates of weak solutions to nondiagonal quasilinear parabolic systems

Dmitry Portnyagin (2005)

Annales Polonici Mathematici

L -estimates of weak solutions are established for a quasilinear non-diagonal parabolic system with a special structure whose leading terms are modelled by p-Laplacians. A generalization of the weak maximum principle to systems of equations is employed.

Estimates of weighted Hölder norms of the solutions to a parabolic boundary value problem in an initially degenerate domain

Antonio Fasano, Vsevolod Solonnikov (2002)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

A-priori estimates in weighted Hölder norms are obtained for the solutions of a one- dimensional boundary value problem for the heat equation in a domain degenerating at time t = 0 and with boundary data involving simultaneously the first order time derivative and the spatial gradient.

Estimates on the solution of an elliptic equation related to Brownian motion with drift.

Joseph G. Conlon, Juan Redondo (1995)

Revista Matemática Iberoamericana

In this paper we are concerned with studying the Dirichlet problem for an elliptic equation on a domain in R3. For simplicity we shall assume that the domain is a ball ΩR of radius R. Thus:ΩR = {x ∈ R3 : |x| < R}.The equation we are concerned with is given by(-Δ - b(x).∇) u(x) = f(x),    x ∈ ΩR,with zero Dirichlet boundary conditions.

Estimations pour ¯ dans des domaines non pseudo-convexes

Maklouf Derridj (1978)

Annales de l'institut Fourier

Nous étudions les domaines Ω de C n qui satisfont (localement) à l’estimation suivante : i , k = 1 n u j z k C ( u + * u + u ) , u 𝒟 0 , 1 ( V Ω ) V est un voisinage d’un point z 0 du bord Ω .L’intérêt de cette estimation réside dans son utilisation pour montrer une estimation sous-elliptique. Remarquons qu’elle est toujours satisfaite par les domaines pseudo-convexes, ce qui rend naturel le fait qu’elle soit liée au comportement dans V des parties négatives des valeurs propres de la forme de Levi.

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