Sökning: "cocycles"

Hittade 3 avhandlingar innehållade ordet cocycles.

  1. 1. On the breakdown of regularity of invariant curves in quasi-periodically forced systems

    Författare :Thomas Ohlson Timoudas; Kristian Bjerklöv; Joaquim Puig; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dynamical systems; strange attractors; Schrödinger cocycles;

    Sammanfattning : In this thesis we study the process of torus collisions in one-parameter families of quasi-periodically forced dynamical systems. Specifically, we study the process whereby two invariant curves (homeomorphic to circles), one attracting and one repelling, bifurcate into a strange non-chaotic attractor. LÄS MER

  3. 2. Stacky Modifications and Operations in the Étale Cohomology of Number Fields

    Författare :Eric Ahlqvist; David Rydh; Alexander Schmidt; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stacks; ramified covers; étale cohomology; cup product; Massey product; Galois cohomology; building data; 2-cocycles; Matematik; Mathematics;

    Sammanfattning : This thesis consists of 4 papers. In Paper A we define stacky building data for stacky covers in the spirit of Pardini and give an equivalence of (2,1)- categories between the category of stacky covers and the category of stacky building data. LÄS MER

  4. 3. Strings, Branes and Symmetries

    Författare :Anders Westerberg; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lie-algebra cohomology; Reggeon vertices; extended objects; string theory; p -branes; current algebra; supersymmetry; sewing; pseudodifferential operators; D-branes;

    Sammanfattning : Recent dramatic progress in the understanding of the non-perturbative structure of superstring theory shows that extended objects of various kinds, collectively referred to as p-branes, are an integral part of the theory. In this thesis, comprising an introductory text divided in two parts and seven appended research papers (Papers I-VII), we study various aspects of p-branes with relevance for superstring theory. LÄS MER