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On some new spectral estimates for Schrödinger-like operators

Daniel Levin (2006)

Open Mathematics

We prove the analog of the Cwikel-Lieb-Rozenblum estimate for a wide class of second-order elliptic operators by two different tools: Lieb-Thirring inequalities for Schrödinger operators with matrix-valued potentials and Sobolev inequalities for warped product spaces.

On the principal eigenvalue of elliptic operators in N and applications

Henry Berestycki, Luca Rossi (2006)

Journal of the European Mathematical Society

Two generalizations of the notion of principal eigenvalue for elliptic operators in N are examined in this paper. We prove several results comparing these two eigenvalues in various settings: general operators in dimension one; self-adjoint operators; and “limit periodic” operators. These results apply to questions of existence and uniqueness for some semilinear problems in the whole space. We also indicate several outstanding open problems and formulate some conjectures.

On the range of elliptic operators discontinuous at one point

Cristina Giannotti (2002)

Bollettino dell'Unione Matematica Italiana

Let L be a second order, uniformly elliptic, non variational operator with coefficients which are bounded and measurable in R d ( d 3 ) and continuous in R d 0 . Then, if Ω R d is a bounded domain, we prove that L W 2 , p Ω is dense in L p Ω for any p 1 , d / 2 .

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