The set of possible spectra $(\lambda,\mu,\nu) $ of zero-sum triples of Hermitian matrices
forms a polyhedral cone, whose facets have been already studied by Knutson and Tao …

This book is an introduction to the representation theory of quivers and finite dimensional
algebras. It gives a thorough and modern treatment of the algebraic approach based on …

We study the left–right action of SL n× SL n on m-tuples of n× n matrices with entries in an
infinite field K. We show that invariants of degree n 2− n define the null cone. Consequently …

Abstract Kostka numbers and Littlewood-Richardson coefficients appear in combinatorics
and representation theory. Interest in their computation stems from the fact that they are …

A representation of a quiver is given by a collection of matrices. Semi-invariants of quivers
can be constructed by taking admissible partial polarizations of the determinant of matrices …

This article is an expository account of the theory of twisted commutative algebras, which
simply put, can be thought of as a theory for handling commutative algebras with large …

We give a description of faces, of all codimensions, for the cones spanned by the set of
weights associated to the rings of semi-invariants of quivers. For a triple flag quiver and its …

We consider two group actions on m-tuples of n× n matrices with entries in the field K. The
first is simultaneous conjugation by GL n and the second is the left-right action of SL n× SL n …

We present a polynomiality property of the Littlewood–Richardson coefficients cλμν. The
coefficients are shown to be given by polynomials in λ, μ and ν on the cones of the chamber …

Recently a new basis for the Hopf algebra of quasisymmetric functions QSym, called
quasisymmetric Schur functions, has been introduced by Haglund, Luoto, Mason, van …