  We study a cohomology-valued hypergeometric series which naturally arises in
the description of (local) mirror symmetry. We identify it as a central charge
formula for BPS states and study its monodromy property from the viewpoint of
Kontsevich's homological mirror symmetry. In the case of local mirror symmetry,
we will identify a symplectic form, and will conjecture an integral and
symplectic monodromy property of a relevant hypergeometric series of
Gel'fand-Kapranov-Zelevinski type.
