sigmoid <=> Gaussian a posteriori distributions

[John B. Hampshire II]

The proof of this linkage (like so many proofs associated
with connectionist models) goes way back... probably
to Gauss.  Before neural networks were in vogue, the
sigmoid was associated with linear classifiers in the
form of the exponential logistic.  So, for example,
guys like Lachenbruch showed the proof in the
context of linear regression/classification in the
60's.

This is meant only to inform, not to kick sand in anybody's face.

-John