Perceptron Training Sets
Let X = X+ U X- be the set of training examples.
SX = X1, X2, ..., Xk, ... is a training sequence on X, provided:
(1) Each Xk is a member of X, and
(2) Each element of X occurs infinitely often in SX.
An element e occurs infinitely often in a sequence
provided that for any nonzero integer i, there exists a nonnegative integer j such that there is an occurrence of e in zi, zi+1, ..., zj.