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    • Generalizations of Quandles to Multi-Linkoids 

      Pflume, Runa (2024-04-10)
      In this thesis, we define the fundamental quandle of knotoids and linkoids and prove that it is invariant under the under forbidden-move and hence encodes only the information of the underclosure of the knotoid. We ...
    • The Spectra on Lie Groups and Its Application to twisted L2-Invariants 

      Han, Zhicheng (2024-02-29)
      We computed spectra of various $G$-invariant differential operators on the universal cover of 2x2 unimodular groups. This was achieved by applying tools from harmonic analysis/representation theory to corresponding groups. ...
    • An Integration Theorem for Representations of the Tangent Algebroid 

      Busche, Geoffrey-Desmond (2024-02-09)
      This dissertation investigates representations of Lie groupoids and Lie algebroids and the connection between them. Lie groupoids and Lie algebroids are differential-geometric generalisations of Lie groups and Lie ...
    • A Wasserstein-like Distance on Vector Fields 

      Sommer, Vincent (2023-10-06)
      We introduce a new distance on the space of vector fields over a Riemannian manifold that is motivated by the construction and properties of the Wasserstein distance. The construction relies on a particular metric on the ...
    • Twisted equivariant K-theory and equivariant T-duality 

      Dove, Thomas (2023-09-18)
      This thesis is about two things: twisted equivariant K-theory and equivariant topological T-duality. First, we prove a fixed point decomposition theorem for twisted equivariant K-theory, generalising a result of Atiyah and ...
    • Novikov-Shubin Invariants of Nilpotent Lie Groups 

      Höpfner, Tim Martin (2023-05-25)
      Novikov-Shubin invariants are so-called L2-invariants of non-compact manifolds. They are defined using the Laplace operators and measure the density of their spectra near zero. This near-zero part of the spectrum is ...
    • Concordances in Positive Scalar Curvature and Index Theory 

      Hertl, Thorsten (2023-02-24)
      We apply the strategy to study of diffeomorphisms via block diffeomorphisms to the world of positive scalar curvature (psc) metrics. For each closed psc manifold, we construct the cubical set of all psc block metrics, the ...
    • Nahms Equations and Nilpotent Orbits 

      Krüger, Christoff (2022-05-31)
      P. Kronheimer has identified certain space of solutions to Nahms equations with a coadjoint orbit of a nilpotent element in a complex, semi-simple Lie algebra and that way equipped the orbit with an hyperkähler structure ...
    • Foliated Positive Scalar Curvature 

      Deng, Jialong (2021-11-11)
      In this thesis we study different questions on scalar curvatures. The first part is devoted to obstructions against existence of a (Riemannian) metric with positive scalar curvature on a closed manifold. The second ...
    • Lie Algebras and the Dimension Problem 

      Sicking, Thomas (2021-11-03)
      The dimension subgroup problem and the Ore conjecture are two group theoretical problems. In this thesis, translations of these problems to Lie algebras are analyzed and partially solved.
    • Investigations in Hadamard spaces 

      Bërdëllima, Arian (2021-08-27)
      This thesis investigates the interplay between geometry and convex analysis in Hadamard spaces. Motivated by numerous applications of CAT(0) geometry, our work builds upon the results in convex analysis and Alexandrov ...
    • Continuous Wavelet Transformation on Homogeneous Spaces 

      Blobel, Burkhard (2021-03-29)
      The classical Continuous Wavelet Transformation (cCWT) is an important and well-studied tool in signal processing and data analysis. Because of its deep connection to representation theory, it has come into focus of pure ...
    • Index theory and groupoids for filtered manifolds 

      Ewert, Eske Ellen (2020-12-21)
      In this thesis, we propose to use generalized fixed point algebras as an approach to the pseudodifferential calculus on filtered manifolds. A filtered manifold is a manifold \(M\) with a filtration of its tangent ...
    • The Barban-Davenport-Halberstam for tuples of k-free numbers 

      Parry, Tomos (2020-10-23)
      An asymptotic formula for variance of tuples of k-free numbers in arithmetic progressions
    • Topological Invariants for Non-Archimedean Bornological Algebras 

      Mukherjee, Devarshi (2020-10-13)
      In this thesis, we define a cyclic homology theory for non-archimedean bornological algebras, which we call analytic cyclic homology. Let V be a complete, discrete valuation ring with uniformiser p, residue field k, and ...
    • Index Theory and Positive Scalar Curvature 

      Seyedhosseini, Mehran (2020-07-24)
      The aim of this dissertation is to use relative higher index theory to study questions of existence and classification of positive scalar curvature metrics on manifolds with boundary. First we prove a theorem relating ...
    • Benjamini-Schramm Convergence of Normalized Characteristic Numbers of Riemannian Manifolds 

      Luckhardt, Daniel (2020-04-30)
      We study a weak form of Gromov-Hausdorff convergence of Riemannian manifolds, also known as Benjamini-Schramm convergence. This concept is also applicable to other areas and has widely been studied in the context of ...
    • A Mayer-Vietoris Spectral Sequence for C*-Algebras and Coarse Geometry 

      Naarmann, Simon (2019-04-10)
      Let $A$ be a C*-algebra that is the norm closure $A = \overline{\sum_{\beta \in \alpha} I_\beta}$ of an arbitrary sum of C*-ideals $I_\beta \subseteq A$. We construct a homological spectral sequence that takes as input the ...
    • Generalized Seiberg-Witten and the Nahm Transform 

      Raymond, Robin (2019-01-11)
      Using the viewpoint of principal bundles on hyperk¨ ahler reductions, we recover the results of Gocho and Nakajima [GN92] and give insights into the role that the quater- nions play. We define a framework for dimensional ...
    • Shape space in terms of Wasserstein geometry and application to quantum physics 

      Lessel, Bernadette (2018-11-26)
      This thesis offers a mathematical framework to treat quantum dynamics without reference to a background structure, but rather by means of the change of the shape of the state. For this, Wasserstein geometry is used. The ...