  We provide formulas for the denominator and superdenominator of a basic
classical type Lie superalgebra for any set of positive roots. We establish a
connection between certain sets of positive roots and the theory of reductive
dual pairs of real Lie groups. As an application of our formulas, we recover
the Theta correspondence for compact dual pairs. Along the way we give an
explicit description of the real forms of basic classical type Lie
superalgebras.
