The goal of this thesis is to examine the actions of finite symmetry groups on aperiodic tilings. To an aperiodic tiling with finite local complexity arising from a primitive substitution rule one can associate a metric space, transformation groupoids, and C*-algebras. Finite symmetry groups of the tiling act on each of these objects and we investigate appropriate constructions on each, namely the orbit space, semidirect product groupoids, and crossed product C*-algebras respectively. Of particular interest are the crossed product C*-algebras; we derive important structure results about them and compute their K-theory.

Thesis (Ph. D.)--University of Oregon, 2001. / Typescript. Includes vita and abstract. Includes bibliographical references (leaf 49). Also available for download via the World Wide Web; free to University of Oregon users.

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The goal of this thesis is to examine the actions of finite symmetry groups on aperiodic tilings. To an aperiodic tiling with finite local complexity arising from a primitive substitution rule one can associate a metric space, transformation groupoids, and C*-algebras. Finite symmetry groups of the tiling act on each of these objects and we investigate appropriate constructions on each, namely the orbit space, semidirect product groupoids, and crossed product C*-algebras respectively. Of particular interest are the crossed product C*-algebras; we derive important structure results about them and compute their K-theory.

Thesis (Ph.D.)--University of Adelaide, School of Mathematical Sciences, Discipline of Pure Mathematics, 2004. / "Submitted September 2002 ... Amended September 2004." Bibliography: p. 152-157.

Univ., Habil.-Schr. u.d.T.: Gohm, Rolf: Elements of a spatial theory for noncommutative stationary processes with discrete time index--Greifswald, 2002. / Literaturverz. S. [165] - 168.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 103-105). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947969.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisors: Willy Fischler and Yuval Neʼeman. Vita. Includes bibliographical references.

We give a formula for the Chern character on the DG category of global matrix factorizations on a smooth scheme $X$ with superpotential $w\in \Gamma(\O_X)$. Our formula takes values in a Cech model for Hochschild homology. Our methods may also be adapted to get an explicit formula for the Chern character for perfect complexes of sheaves on $X$ taking values in right derived global sections of the De-Rham algebra. Along the way we prove that the DG version of the Chern Character coincides with the classical one for perfect complexes.

A formulação de uma teoria da relatividade geral em espaços não-comutativos tem sido investigada usando-se diferentes abordagens atualmente. Neste contexto, é feita uma revisão do formalismo que descreve a não-comutatividade do espaço-tempo. A seguir, são investigadas as interações entre os campos do gráviton e o bóson escalar, formuladas em um espaço comutativo mostrando-se um método alternativo para reescrever a ação desta interação. Finalmente, utilizando-se este método, obtém-se o termo dominante da ação de interação entre os campos do gráviton e escalar em espaços não-comutativos. Deste modo, somos levados a considerar transformações de coordenadas restritas, com parâmetro infinitesimal "~ 'SOBRE' W "POT.'mü'"(x) tal que " " IND.'mü'"~ 'SOBRE' W "POT.'mü'" = 0. Temos assim a versão não-comutativa da gravidade unimodular / The formulation of a general relativity theory on noncommutative spaces has been investigated using many different approaches. In this context, a revision of the formalism that describes noncommutative spacetime is made. Next, the interactions between the fields of graviton and scalar is investigated in a commutative space showing an alternative method to rewrite the action of this interaction. Finally, using this method, one obtains the dominant term of the action of graviton interacting with a scalar particle in a noncomutative space. In this way, we are led to consider restricted transformations with infinitesimal parameter wμ(x), such that, ∂μ ˜ wμ = 0. Thus we have the noncommutative version of unimodular gravity.