Displaying similar documents to “Differential operators of the first order with degenerate principal symbols”

On Kelvin type transformation for Weinstein operator

Martina Šimůnková (2001)

Commentationes Mathematicae Universitatis Carolinae

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The note develops results from [5] where an invariance under the Möbius transform mapping the upper halfplane onto itself of the Weinstein operator W k : = Δ + k x n x n on n is proved. In this note there is shown that in the cases k 0 , k 2 no other transforms of this kind exist and for case k = 2 , all such transforms are described.

Existence of Solution for Quasilinear Degenerated Elliptic Unilateral Problems

Youssef Akdim, Elhoussine Azroul, Abdelmoujib Benkirane (2003)

Annales mathématiques Blaise Pascal

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An existence theorem is proved, for a quasilinear degenerated elliptic inequality involving nonlinear operators of the form A u + g ( x , u , u ) , where A is a Leray-Lions operator from W 0 1 , p ( Ω , w ) into its dual, while g ( x , s , ξ ) is a nonlinear term which has a growth condition with respect to ξ and no growth with respect to s , but it satisfies a sign condition on s , the second term belongs to W - 1 , p ( Ω , w * ) .

On the solvability of nonlinear elliptic equations in Sobolev spaces

Piotr Fijałkowski (1992)

Annales Polonici Mathematici

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We consider the existence of solutions of the system (*) P ( D ) u l = F ( x , ( α u ) ) , l = 1,...,k, x n ( u = ( u ¹ , . . . , u k ) ) in Sobolev spaces, where P is a positive elliptic polynomial and F is nonlinear.

On some shift invariant integral operators, univariate case

George A. Anastassiou, Heinz H. Gonska (1995)

Annales Polonici Mathematici

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In recent papers the authors studied global smoothness preservation by certain univariate and multivariate linear operators over compact domains. Here the domain is ℝ. A very general positive linear integral type operator is introduced through a convolution-like iteration of another general positive linear operator with a scaling type function. For it sufficient conditions are given for shift invariance, preservation of global smoothness, convergence to the unit with rates, shape preserving...