  By examining multi-instantons in N=2 supersymmetric SU(2) gauge theory, we
derive, on very general grounds, and to all orders in the instanton number, a
relationship between the prepotential F(Phi), and the coordinate on the quantum
moduli space u=<Tr Phi^2>. This relation was previously obtained by Matone in
the context of the explicit Seiberg-Witten low-energy solution of the model.
Our findings can be viewed as a multi-instanton check of the proposed exact
results in supersymmetric gauge theory.
