Search for dissertations about: "Bruhat"

Found 5 swedish dissertations containing the word Bruhat.

  2. 1. Combinatorial complexes, Bruhat intervals and reflection distances

    Author : Axel Hultman; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; MATHEMATICS; MATEMATIK;

    Abstract : The various results presented in this thesis are naturallysubdivided into three different topics, namely combinatorialcomplexes, Bruhat intervals and expected reflection distances.Each topic is made up of one or several of the altogether sixpapers that constitute the thesis. READ MORE

  4. 2. Generalised Ramsey numbers and Bruhat order on involutions

    Author : Mikael Hansson; Axel Hultman; Jan Snellman; Jonas Sjöstrand; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : This thesis consists of two papers within two different areas of  combinatorics.Ramsey theory is a classic topic in graph theory, and Paper A deals with two of its most fundamental problems: to compute Ramsey numbers and to characterise critical graphs. More precisely, we study generalised Ramsey numbers for two sets Γ1 and Γ2 of cycles. READ MORE

  5. 3. Enumerative combinatorics related to partition shapes

    Author : Jonas Sjöstrand; Anders Björner; Christian Krattenthaler; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; partition shape; sign-imbalance; Robinson-Schensted correspondence; chess tableau; restricted word; cylindrical lattice walk; Poincaré polynomial; Bruhat interval; rook polynomial; pattern avoidance; partitionsform; teckenobalans; Robinson-Schensted-korrespondens; schacktablå; begränsade ord; cylindriska latticestigar; poincarépolynom; bruhatintervall; tornpolynom; mönsterundvikande permutation; MATHEMATICS; MATEMATIK;

    Abstract : This thesis deals with enumerative combinatorics applied to three different objects related to partition shapes, namely tableaux, restricted words, and Bruhat intervals. The main scientific contributions are the following. READ MORE

  6. 4. Boolean complexes of involutions and smooth intervals in Coxeter groups

    Author : Vincent Umutabazi; Axel Hultman; Jan Snellman; Christian Stump; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : This dissertation is composed of four papers in algebraic combinatorics related to Coxeter groups. By a Coxeter group, we mean a group W generated by a subset S ⊂ W such that for all s ∈ S , we have s2 = e, and (s, s′)m(s,s′) = (s′ s)m(s,s′) = e, where m(s, s′) = m(s′ s) ≥ 2 for all s ≠ s′ ≥ ∈ S . READ MORE

  7. 5. Combinatorics and topology related to involutions in Coxeter groups

    Author : Mikael Hansson; Axel Hultman; Jan Snellman; Nathan Reading; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : This dissertation consists of three papers in combinatorial Coxeter group theory.A Coxeter group is a group W generated by a set S, where all relations can be derived from the relations s2 = e for all s ? S, and (ss′)m(s,s′) = e for some pairs of generators s ≠ s′ in S, where e ? W is the identity element and m(s, s′) is an integer satisfying that m(s, s′) = m(s′, s) ≥ 2. READ MORE