We consider commutation relations and invertibility relations of vertex operators for the quantum affine superalgebra Uq( sl(M |N )) by using bosonization. We show that vertex operators give a representation of the graded Zamolodchikov-Faddeev algebra by direct computation. Invertibility relations of type-II vertex operators for N > M are very similar to those of type-I for M > N .
IntroductionVertex operators and corner transfer matrices are a useful tool in solvable lattice models [1,2,3]. They can be very effective way of calculating correlation functions. In the thermodynamic limit, a half transfer matrix becomes a type-I vertex operator Φ µV λ (z) of the quantum affine algebra U q (g). A type-I vertex operator is, by definition, an intertwiner of theand V (µ) are highest weight representations and V z denotes the evaluation representation [4]. In this paper we consider commutation relations and invertibility relations of the vertex operators for U q ( sl(M |N )) (M = N, M, N ≥ 1) by using bosonization [5]. We show that the vertex operators give a representation of the graded Zamolodchikov-Faddeev algebra by direct computation. Our commutation relations of the vertex operators give a higher-rank generalization of those for U q ( sl(M |1)) [6,7]. A type-. We note that the invertibility relations of the type-II vertex operators for N > M are very similar to those of the type-I for M > N . Our direct computation can be applied to bosonization of vertex operators and a L-operator for the elliptic algebra U q,p ( sl(M |N )) [8,9,10]. Moreover, quantum W -algebra W q,p (sl(M |N )) will arise as fusion of vertex operators for the elliptic algebra [11].The text is organized as follows. In Section 2 we recall bosonization of the quantum affine superalgebra U q ( sl(M |N )) and the vertex operators. In Section 3 we introduce the R-matrix and describe the main theorems. In Section 4 we give a direct proof of the main theorems. In Section 5 we discuss related topics. In Appendix A we summarize normal ordering rules of bosonic operators.where we set δ(z) = m∈Z z m . Here we use the generating functions(2.24)The Chevalley generators are obtained by h i = H i 0 (i = 1, 2, · · · , M + N − 1), (2.25) e i = X +,i 0 , f i = X −,i 0 (i = 1, 2, · · · , M + N − 1), (2.26)