Ben Brubaker

  1. Whittaker Functions and Demazure Operators.

    Authors: Ben Brubaker, Daniel Bump, Anthony Licata
    Subjects: Representation Theory
    Abstract

    We consider a natural basis of the Iwahori fixed vectors in the Whittaker
    model of an unramified principal series representation of a split semisimple p-
    adic group, indexed by the Weyl group. We show that the elements of this basis
    may be computed from one another by applying Demazure-Lusztig operators. The
    precise identities involve correction terms, which may be calculated by a
    combinatorial algorithm that is identical to the computation of the fibers of
    the Bott-Samelson resolution of a Schubert variety.

  2. Weyl group multiple Dirichlet series of type C.

    Authors: Ben Brubaker, Jennifer Beineke, Sharon Frechette
    Subjects: Number Theory
    Abstract

    We develop the theory of Weyl group multiple Dirichlet series for root
    systems of type C. For an arbitrary root system of rank r and a positive
    integer n, these are Dirichlet series in r complex variables with analytic
    continuation and functional equations isomorphic to the associated Weyl group.
    In type C, they conjecturally arise from the Fourier-Whittaker coefficients of
    minimal parabolic Eisenstein series on an n-fold metaplectic cover of SO(2r+1).
    For any odd n, we construct an infinite family of Dirichlet series
    conjecturally satisfying the above analytic properties.

  3. Schur Polynomials and the Yang-Baxter equation.

    Authors: Ben Brubaker, Daniel Bump, Solomon Friedberg
    Subjects: Combinatorics
    Abstract

    We show that within the six-vertex model there is a parametrized Yang-Baxter
    equation with nonabelian parameter group GL(2)xGL(1) at the center of the
    disordered regime. As an application we rederive deformations of the Weyl
    character formule of Tokuyama and of Hamel and King.

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