Displaying similar documents to “Discreteness of the spectrum for some differential operators with unbounded coefficients in R n

On a class of elliptic operators with unbounded coefficients in convex domains

Giuseppe Da Prato, Alessandra Lunardi (2004)

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

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We study the realization A of the operator A = 1 2 - ( D U , D ) in L 2 Ω , μ , where Ω is a possibly unbounded convex open set in R N , U is a convex unbounded function such that lim x Ω , x Ω U x = + and lim x + , x Ω U x = + , D U x is the element with minimal norm in the subdifferential of U at x , and μ d x = c exp - 2 U x d x is a probability measure, infinitesimally invariant for A . We show that A , with domain D A = u H 2 Ω , μ : D U , D u L 2 Ω , μ is a dissipative self-adjoint operator in L 2 Ω , μ . Note that the functions in the domain of A do not satisfy any particular boundary condition. Log-Sobolev and Poincaré inequalities...

Scattering properties for a pair of Schrödinger type operators on cylindrical domains

Michael Melgaard (2007)

Open Mathematics

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Strong asymptotic completeness is shown for a pair of Schrödinger type operators on a cylindrical Lipschitz domain. A key ingredient is a limiting absorption principle valid in a scale of weighted (local) Sobolev spaces with respect to the uniform topology. The results are based on a refined version of Mourre’s method within the context of pseudo-selfadjoint operators.

On the H p - L q boundedness of some fractional integral operators

Pablo Rocha, Marta Urciuolo (2012)

Czechoslovak Mathematical Journal

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Let A 1 , , A m be n × n real matrices such that for each 1 i m , A i is invertible and A i - A j is invertible for i j . In this paper we study integral operators of the form T f ( x ) = k 1 ( x - A 1 y ) k 2 ( x - A 2 y ) k m ( x - A m y ) f ( y ) d y , k i ( y ) = j 2 j n / q i ϕ i , j ( 2 j y ) , 1 q i < , 1 / q 1 + 1 / q 2 + + 1 / q m = 1 - r , 0 r < 1 , and ϕ i , j satisfying suitable regularity conditions. We obtain the boundedness of T : H p ( n ) L q ( n ) for 0 < p < 1 / r and 1 / q = 1 / p - r . We also show that we can not expect the H p - H q boundedness of this kind of operators.