Generalizing the super duality formalism for finite-dimensional Lie
superalgebras of type ABCD, we establish an equivalence between parabolic BGG
categories of a Kac-Moody Lie superalgebra and a Kac-Moody Lie algebra. The
characters for a large family of irreducible highest weight modules over a
symmetrizable Kac-Moody Lie superalgebra are then given in terms of
Kazhdan-Lusztig polynomials for the first time. We formulate a notion of
integrable modules over a symmetrizable Kac-Moody Lie superalgebra via super
duality, and show that these integrable modules form a semisimple tensor
subcategory, whose Littlewood-Richardson tensor product multiplicities coincide
with those in the Kac-Moody algebra setting.Comment: 28 page