Sökning: "Roland Häggkvist"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Roland Häggkvist.

  1. 1. On Latin squares and avoidable arrays

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

    Sammanfattning : 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. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  4. 3. On some graph coloring problems

    Författare :Carl Johan Casselgren; Roland Häggkvist; Svante Linusson; Umeå universitet; []
    Nyckelord :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;

    Sammanfattning : .... LÄS MER

  5. 4. Snarks : Generation, coverings and colourings

    Författare :Jonas Hägglund; Roland Häggkvist; Klas Markström; Luis Goddyn; Umeå universitet; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  7. 5. Three Kotzig graphs form a good frame

    Författare :Abid Khan; Roland Häggkvist; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER