Edward Richmond

  1. A combinatorial characterization of tight fusion frames.

    Authors: Edward Richmond, Kurt Luoto, Marcin Bownik
    Subjects: Functional Analysis
    Abstract

    In this paper we give a combinatorial characterization of tight fusion frame
    (TFF) sequences using Littlewood-Richardson skew tableaux. The equal rank case
    has been solved recently by Casazza, Fickus, Mixon, Wang, and Zhou. Our
    characterization does not have this limitation. We also develop some methods
    for generating TFF sequences. The basic technique is a majorization principle
    for TFF sequences combined with spatial and Naimark dualities. We use these
    methods and our characterization to give necessary and sufficient conditions
    which are satisfied by the first three highest ranks.

  2. Branching Schubert calculus and the Belkale-Kumar product on cohomology.

    Authors: Nicolas Ressayre, Edward Richmond
    Subjects: Algebraic Geometry
    Abstract

    In 2006, Belkale and Kumar define a new product on the cohomology of flag
    varieties and use this new product to give an improved solution to the
    eigencone problem for complex reductive groups. In this paper, we give a
    generalization of the Belkale-Kumar product to the branching Schubert calculus
    setting. The study of Branching Schubert calculus attempts to understand the
    induced map on cohomology of an equivariant embedding of flag varieties. The
    main application of our work is a compact formulation of the solution to the
    branching eigencone problem.

  3. Branching Schubert calculus and the Belkale-Kumar product on cohomology.

    Authors: Nicolas Ressayre, Edward Richmond
    Subjects: Algebraic Geometry
    Abstract

    In 2006, Belkale and Kumar define a new product on the cohomology of flag
    varieties and use this new product to give an improved solution to the
    eigencone problem for complex reductive groups. In this paper, we give a
    generalization of the Belkale-Kumar product to the branching Schubert calculus
    setting. The study of Branching Schubert calculus attempts to understand the
    induced map on cohomology of an equivariant embedding of flag varieties. The
    main application of our work is a compact formulation of the solution to the
    branching eigencone problem.

Syndicate content