2. Let t be a discrete domain, and let H Singleton 2E X} U{h-), where for each z E X, hz is the function defined by (a) 1 if x z and hz(z) 0 iz. h-is simply the all-negative hypothesis, namely, Vz E X, h-(x) = 0. The realizability assumption here implies that the true hypothesis f labels negatively all examples in the domain, perhaps except one. 2. Let t be a discrete domain, and let H Singleton 2E X} U{h-), where for each z E X, hz is the function defined by (a) 1 if x z and hz(z) 0 iz. h-is simply the all-negative hypothesis, namely, Vz E X, h-(x) = 0. The realizability assumption here implies that the true hypothesis f labels negatively all examples in the domain, perhaps except one