Seja A a C*-álgebra dos operadores limitados em L^2(RxS^1) gerada por: operadores a(M) de multiplicação por funções a em C^{\\infty}(S^1), operadores b(M) de multiplicação por funções b em C([-\\infty, + \\infty]), operadores de multiplicação por funções contínuas 2\\pi-periódicas, \\Lambda = (1-\\Delta_{RxS^1})^{-1/2}, onde \\Delta_{RxS^1} é o Laplaciano de RxS^1, e \\partial_t \\Lambda, \\partial_x \\Lambda para t em R e x em S^1. Calculamos a K-teoria de A e de A/K(L^2(RxS^1)), onde K(L^2(RxS^1)) é o ideal dos operadores compactos em L^2(RxS^1). / 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_t \\Lambda, \\partial_x \\Lambda, for t in R and x in S^1. We compute the K-theory of A and A/K(L^2(RxS^1)), where K(L^2(RxS^1))$ is the ideal of compact operators on L^2(RxS^1).

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Mathematics. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 119-121. / Ph.D.

Seja A a C*-álgebra dos operadores limitados em L^2(RxS^1) gerada por: operadores a(M) de multiplicação por funções a em C^{\\infty}(S^1), operadores b(M) de multiplicação por funções b em C([-\\infty, + \\infty]), operadores de multiplicação por funções contínuas 2\\pi-periódicas, \\Lambda = (1-\\Delta_{RxS^1})^{-1/2}, onde \\Delta_{RxS^1} é o Laplaciano de RxS^1, e \\partial_t \\Lambda, \\partial_x \\Lambda para t em R e x em S^1. Calculamos a K-teoria de A e de A/K(L^2(RxS^1)), onde K(L^2(RxS^1)) é o ideal dos operadores compactos em L^2(RxS^1). / 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_t \\Lambda, \\partial_x \\Lambda, for t in R and x in S^1. We compute the K-theory of A and A/K(L^2(RxS^1)), where K(L^2(RxS^1))$ is the ideal of compact operators on L^2(RxS^1).

The paper is devoted to pseudodifferential boundary value problems in domains with singular points on the boundary. The tangent cone at a singular point is allowed to degenerate. In particular, the boundary may rotate and oscillate in a neighbourhood of such a point. We show a criterion for the Fredholm property of a boundary value problem and derive estimates of solutions close to singular points.

For general elliptic pseudodifferential operators on manifolds with singular points, we prove an algebraic index formula. In this formula the symbolic contributions from the interior and from the singular points are explicitly singled out. For two-dimensional manifolds, the interior contribution is reduced to the Atiyah-Singer integral over the cosphere bundle while two additional terms arise. The first of the two is one half of the 'eta' invariant associated to the conormal symbol of the operator at singular points. The second term is also completely determined by the conormal symbol. The example of the Cauchy-Riemann operator on the complex plane shows that all the three terms may be non-zero.

On a compact closed manifold with edges live pseudodifferential operators which are block matrices of operators with additional edge conditions like boundary conditions in boundary value problems. They include Green, trace and potential operators along the edges, act in a kind of Sobolev spaces and form an algebra with a wealthy symbolic structure. We consider complexes of Fréchet spaces whose differentials are given by operators in this algebra. Since the algebra in question is a microlocalization of the Lie algebra of typical vector fields on a manifold with edges, such complexes are of great geometric interest. In particular, the de Rham and Dolbeault complexes on manifolds with edges fit into this framework. To each complex there correspond two sequences of symbols, one of the two controls the interior ellipticity while the other sequence controls the ellipticity at the edges. The elliptic complexes prove to be Fredholm, i.e., have a finite-dimensional cohomology. Using specific tools in the algebra of pseudodifferential operators we develop a Hodge theory for elliptic complexes and outline a few applications thereof.

The paper is devoted to pseudodifferential boundary value problems in domains with cuspidal wedges. Concerning the geometry we even admit a more general behaviour, namely oscillating cuspidal wedges. We show a criterion for the Fredholm property of a boundary value problem and derive estimates of solutions close to edges.

We describe a new algebra of boundary value problems which contains Lopatinskii elliptic as well as Toeplitz type conditions. These latter are necessary, if an analogue of the Atiyah-Bott obstruction does not vanish. Every elliptic operator is proved to admit up to a stabilisation elliptic conditions of such a kind. Corresponding boundary value problems are then Fredholm in adequate scales of spaces. The crucial novelty consists of the new type of weighted Sobolev spaces which serve as domains of pseudodifferential operators and which fit well to the nature of operators.

We develop a new approach to the analysis of pseudodifferential operators with small parameter 'epsilon' in (0,1] on a compact smooth manifold X. The standard approach assumes action of operators in Sobolev spaces whose norms depend on 'epsilon'. Instead we consider the cylinder [0,1] x X over X and study pseudodifferential operators on the cylinder which act, by the very nature, on functions depending on 'epsilon' as well. The action in 'epsilon' reduces to multiplication by functions of this variable and does not include any differentiation. As but one result we mention asymptotic of solutions to singular perturbation problems for small values of 'epsilon'.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 51-56).