Search for dissertations about: "groupoid"

Showing result 1 - 5 of 9 swedish dissertations containing the word groupoid.

  2. 1. A Categorical Study of Composition Algebras via Group Actions and Triality

    Author : Seidon Alsaody; Ernst Dieterich; Ryszard Rubinsztein; Alberto Elduque; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Composition algebra; division algebra; absolute valued algebra; triality; groupoid; group action; algebraic group; Lie algebra of derivations; classification.; Mathematics; Matematik;

    Abstract : A composition algebra is a non-zero algebra endowed with a strictly non-degenerate, multiplicative quadratic form. Finite-dimensional composition algebras exist only in dimension 1, 2, 4 and 8 and are in general not associative or unital. Over the real numbers, such algebras are division algebras if and only if they are absolute valued, i.e. READ MORE

  4. 2. Modeling mapping spaces with short hammocks

    Author : Sebastian Öberg; Wojciech Chachólski; Fernando Muro; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mapping spaces; hammocks; homotopy theory; category theory; Matematik; Mathematics;

    Abstract : We construct a category of short hammocks and show that it has the weak homotopy type of mapping spaces. In doing so we tackle the problem of applying the nerve to large categories without the use of multiple universes. We also explore what the mapping space is. READ MORE

  5. 3. Admissible covers, modular operads and modular forms

    Author : Dan Petersen; Carel Faber; Alessandro Chiodo; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : This thesis contains three articles related to operads and moduli spaces of admissible covers of curves. In Paper A we isolate cohomology classes coming from modular forms inside a certain space of admissible covers, thereby showing that this moduli space can be used as a substitute for a Kuga–Sato variety. READ MORE

  6. 4. Localic Categories of Models and Categorical Aspects of Intuitionistic Ramified Type Theory

    Author : Johan Lindberg; Erik Palmgren; Peter LeFanu Lumsdaine; Henrik Forssell; Benno van den Berg; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Topos theory; predicative topos theory; ramified type theory; type theory; localic groupoids; Mathematics; matematik;

    Abstract : This thesis contains three papers, all in the general area of categorical logic, together with an introductory part with some minor results and proofs of known results which does not appear to be (easily) available in the literature.In Papers I and II we investigate the formal system Intuitionistic Ramified Type Theory (IRTT), introduced by Erik Palmgren, as an approach to predicative topos theory. READ MORE

  7. 5. Amenable-like properties of étale groupoids

    Author : Gabriel Favre; Sven Raum; Nadia Larsen; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Etale groupoids; Representation theory; amenability; inverse semigroups; C*-algebra; matematik; Mathematics;

    Abstract : This thesis consists of three papers related to analytic and representation theoretic properties of étale groupoids.In the first paper, we characterize algebraically the type I and CCR property for ample groupoids and their non-commutative duals: Boolean inverse semigroups. Our results use and generalize Thoma’s work on discrete groups. READ MORE