Approximation of Boolean Functions by Sigmoidal Networks: Part I: XOR and Other Two-Variable Functions
E. K. Blum · Neural Computation · 1989
We prove the existence of a manifold of exact solutions (mean-square error E = 0) of weights and thresholds for sigmoidal networks for XOR and other 2-variable Boolean functions. We also prove the existence of a manifold of local minima of E where E ≠ 0.