  In this paper, we present a simple combinatorial proof of a Weyl type formula
for hook Schur polynomials, which has been obtained by using a Kostant type
cohomology formula for $\frak{gl}_{m|n}$. In general, we can obtain in a
combinatorial way a Weyl type formula for various highest weight
representations of a Lie superalgebra, which together with a general linear
algebra forms a Howe dual pair.
