  A proof that the prepotential for pure N=2 Super-Yang-Mills theory associated
with Lie algebras B_r and C_r satisfies the generalized WDVV
(Witten-Dijkgraaf-Verlinde-Verlinde) system was given by Marshakov, Mironov and
Morozov. Among other things, they use an associative algebra of holomorphic
differentials. Later Ito and Yang used a different approach to try to
accomplish the same result, but they encountered objects of which it is unclear
whether they form structure constants of an associative algebra. We show by
explicit calculation that these objects are none other than the structure
constants of the algebra of holomorphic differentials.
