  By using the Y(gl(m|n)) super Yangian symmetry of the SU(m|n) supersymmetric
Haldane-Shastry spin chain, we show that the partition function of this model
satisfies a duality relation under the exchange of bosonic and fermionic spin
degrees of freedom. As a byproduct of this study of the duality relation, we
find a novel combinatorial formula for the super Schur polynomials associated
with some irreducible representations of the Y(gl(m|n)) Yangian algebra.
Finally, we reveal an intimate connection between the global SU(m|n) symmetry
of a spin chain and the boson-fermion duality relation.
