Pseudodifferential Operators
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. K-Teoria e aplicações para cálculos pseudodiferenciais globais e seus problemas de fronteira / K-Theory and applications for global pseudodifferential calculus and its boundary problems.
Nesta tese vamos apresentar dois resultados a respeito de K-teoria de álgebras C^{*} de classes de operadores pseudodiferenciais que são globalmente definidos em \\mathbb^. O primeiro resultado é a prova da regularidade da função \\eta para operadores clássicos com símbolos de Shubin. Vamos mostrar que a álgebra de operadores pseudodiferenciais em \\
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/08/2012
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2. O caráter de Chern-Connes para C*-sistemas dinâmicos calculado em algumas álgebras de operadores pseudodiferenciais / The C*-dynamical system Chern-Connes character computed in some pseudodifferential operators algebras
Given a C$^*$-dynamical system $(A, G, \alpha)$ one defines a homomorphism, called the Chern-Connes character, that take an element in $K_0(A) \oplus K_1(A)$, the K-theory groups of the C$^*$-algebra $A$, and maps it into $H_{\mathbb}^*(G)$, the real deRham cohomology ring of $G$. We explictly compute this homomorphism for the examples $(\overline{\Psi_^0(S^
Publicado em: 2008
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3. K-theory of pseudodifferential operators with semi-periodic symbols on a cylinder / K-Teoria de operadores pseudodiferenciais com símbolos semi-periódicos no cilindro
Let A denote the C*-algebra of bounded operators on L^2(RxS^1) generated by: all multiplications a(M) by functions a in C^{\infty}(S^1), all multiplications b(M) by functions b in C([-\infty, + \infty]), all multiplications by 2\pi-periodic continuous functions, \Lambda = (1-\Delta_{RxS^1)^{-1/2}, where \Delta_{RxS^1} is the Laplacian on RxS^1, and \partial_
Publicado em: 2008
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4. On positivity of pseudo-differential operators
In this paper we obtain new lower bounds for pseudo-differential operators with non-negative symbols, thus providing a sharper form of Gårding's inequality.
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5. Symplectic geometry and positivity of pseudo-differential operators
In this paper we establish positivity for pseudo-differential operators under a condition that is essentially also necessary. The proof is based on a microlocalization procedure and a geometric lemma.
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6. On the lowest eigenvalue of a pseudo-differential operator
Positive lower bounds for pseudo-differential operators with nonnegative symbols are derived; the bounds in particular yield subelliptic estimates for operators arising as sums of squares of vector fields.
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7. A Class of Bounded Pseudo-Differential Operators
Pseudo-differential operators of order -M and type ρ, δ1, δ2 are shown to be bounded in L2 provided that 0 ≤ ρ ≤ δ1 < 1, 0 ≤ ρ ≤ δ2 < 1, and [Formula: see text].
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8. A new class of pseudo-differential operators
We describe a class of pseudo-differential operators and their singular integral realizations and show how these may be used to give precise estimates in various function spaces. Application will be given in particular to several situations in which subelliptic estimates arise for partial differential equations.
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9. Classes of Spatially Inhomogeneous Pseudodifferential Operators
One can obtain sharp information on a pseudodifferential operator p(x,D) by embedding the symbol p in a symbolic calculus specially designed to reflect the behavior of p. We sketch the development of symbolic calculi arising in this connection, and use our results to give simple proofs of the sharp Gårding inequality and of sufficiency of Nirenberg-Traves'
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10. Excision in algebraic K-theory and Karoubi's conjecture.
We prove that the property of excision in algebraic K-theory is for a Q-algebra A equivalent to the H-unitality of the latter. Our excision theorem, in particular, implies Karoubi's conjecture on the equality of algebraic and topological K-theory groups of stable C*-algebras. It also allows us to identify the algebraic K-theory of the symbol map in the theor
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11. Laws of composition of Bäcklund transformations and the universal form of completely integrable systems in dimensions two and three
Bäcklund transformations are defined as operations on solutions of a Riemann boundary value problem (vector bundles over P1) that add apparent singularities. For solutions of difference and differential linear spectral problems, Bäcklund transformations are presented in explicit form through the Christoffel formula and its generalizations. Identities satis