Search for dissertations about: "Families of cycles"

Showing result 1 - 5 of 6 swedish dissertations containing the words Families of cycles.

  2. 1. Families of cycles and the Chow scheme

    Author : David Rydh; Dan Laksov; Martin Olsson; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Families of cycles; Chow scheme; Hilbert scheme; zero-cycles; divided powers; symmetric tensors; symmetric product; Weil restriction; norm functor; Algebra and geometry; Algebra och geometri;

    Abstract : The objects studied in this thesis are families of cycles on schemes. A space — the Chow variety — parameterizing effective equidimensional cycles was constructed by Chow and van der Waerden in the first half of the twentieth century. Even though cycles are simple objects, the Chow variety is a rather intractable object. READ MORE

  4. 2. Snarks : Generation, coverings and colourings

    Author : Jonas Hägglund; Roland Häggkvist; Klas Markström; Luis Goddyn; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Snarks; cubic graphs; enumeration; cycle covers; perfect matching covers; Fulkerson s conjecture; strong cycle double cover conjecture; cycle decompositions; stable cycles; oddness; circumference; uncolourability measures; Mathematics; matematik;

    Abstract : For a number of unsolved problems in graph theory such as the cycle double cover conjecture, Fulkerson's conjecture and Tutte's 5-flow conjecture it is sufficient to prove them for a family of graphs called snarks. Named after the mysterious creature in Lewis Carroll's poem, a \emph{snark} is a cyclically 4-edge connected 3-regular graph of girth at least 5 which cannot be properly edge coloured using three colours. READ MORE

  5. 3. Adolescent pregnancies in Nicaragua. The importance of education

    Author : Elmer Zelaya Blandon; Umeå universitet; []
    Keywords : adolescent; contraception; sexuality; pregnancy; gender; education; Nicaragua;

    Abstract : Early adolescent pregnancy implies increased social and medical risks. There is lack of understanding of the mechanisms behind early sexual debut and pregnancy. This contributes to the difficulties to meet the educational and health care needs of adolescents. READ MORE

  6. 4. Modelling macroeconomic time series with smooth transition autoregressions

    Author : Joakim Skalin; Handelshögskolan i Stockholm; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Among the parametric nonlinear time series model families, the smooth transition regression (STR) model has recently received attention in the literature. The considerations in this dissertation focus on the univariate special case of this model, the smooth transition autoregression (STAR) model, although large parts of the discussion can be easily generalised to the more general STR case. READ MORE

  7. 5. Atom probe tomography of Zircaloy-2 exposed to boiling water reactor operation

    Author : Johan Eriksson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nuclear fuel claddings; Zirconium alloys; Boiling water reactor; Clustering; Atom probe tomography; Radiation effects; Zircaloy-2; Dislocation loops;

    Abstract : Zirconium alloys are used as cladding tubes for the fuel in nuclear reactors. In boiling water reactors (BWRs), the alloy Zircaloy-2, which contains the alloying elements Sn, Fe, Cr, Ni, and O, is commonly used. READ MORE