The Varchenko Determinant of a Coxeter Arrangement

The Varchenko determinant is the determinant of a matrix defined from an arrangement of hyperplanes. Varchenko proved that this determinant has a beautiful factorization. It is, however, not possible to use this factorization to compute a Varchenko determinant from a certain level of complexity. Precisely at this point, we provide an explicit formula of this determinant for the hyperplane arrangements associated to the finite Coxeter groups. The intersections of hyperplanes with the chambers of such arrangements have nice properties which play a central role for the calculation of their relating determinants.Comment: 12 page

Diagonalizability of elements of a group algebra

Let G be a group and K a fields of characteristic 0. Let f be an element of the group algebra K[G]. Let X(f) be the matrix of the left-multiplication action of f on K[G]. We determine the eigenvalues and their multiplicities of X(f) when f is a central element of G, when f is an element of the descent algebra of K[G] for a coxeter group G, and when f is a special element of K[G] for a symmetric group G