2000/12/07 by Maxim Nazarov, Vitaly Tarasov · 1 citation
Mathematics · #math.QA #math.CO #math.RT
published as Duke Math. J. 112 (2002), 343-378 · 29 pages, AmS-TeX, with additions to Section 4
arxiv created 2000/12/07 · arxiv updated 2009/11/30
We study the tensor product W of any number of "elementary" irreducible modules V1,...,Vk over the Yangian of the general linear Lie algebra. Each of these modules is determined by a skew Young diagram and a complex parameter. For any indices i,j=1,...,k there is a canonical non-zero intertwining operator Aij between the tensor products Vi⊗ Vj and Vj⊗ Vi. This operator is defined up to a scalar multipler. We show that the tensor product W is irreducible, if and only if all operators Aij with i<j are invertible. This implies that the Yangian module W is irreducible, if and only if all pairwise tensor products Vi⊗ Vj with i<j are irreducible. We also introduce the notion of a Durfee rank of a skew Young diagram. For an ordinary Young diagram, this is the length of its main diagonal.