Search for dissertations about: "Roland Häggkvist"

Showing result 1 - 5 of 8 swedish dissertations containing the words Roland Häggkvist.

  1. 1. On Latin squares and avoidable arrays

    Author : Lina J. Andrén; Roland Häggkvist; Kimmo Eriksson; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Latin square; avoidability; avoidable array; Discrete mathematics; Diskret matematik; Mathematics; matematik;

    Abstract : This thesis consists of the four papers listed below and a survey of the research area. I Lina J. Andrén: Avoiding (m, m, m)-arrays of order n = 2k II Lina J. Andrén: Avoidability of random arrays III Lina J. READ MORE

  2. 2. On the Ising problem and some matrix operations

    Author : Daniel Andrén; Roland Häggkvist; Henrik Eriksson; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ising problem; phase tansition; matrix multiplicatoin; matrix inversion; Discrete mathematics; Diskret matematik;

    Abstract : The first part of the dissertation concerns the Ising problem proposed to Ernst Ising by his supervisor Wilhelm Lenz in the early 20s. The Ising model, or perhaps more correctly the Lenz-Ising model, tries to capture the behaviour of phase transitions, i.e. how local rules of engagement can produce large scale behaviour. READ MORE

  3. 3. On some graph coloring problems

    Author : Carl Johan Casselgren; Roland Häggkvist; Svante Linusson; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; List coloring; interval edge coloring; coloring graphs from random lists; biregular graph; avoiding arrays; Latin square; scheduling; Discrete mathematics; Diskret matematik; Mathematics; matematik;

    Abstract : .... READ MORE

  4. 4. Snarks : Generation, coverings and colourings

    Author : Jonas Hägglund; Roland Häggkvist; Klas Markström; Luis Goddyn; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; 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. 5. Three Kotzig graphs form a good frame

    Author : Abid Khan; Roland Häggkvist; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : .... READ MORE