In this paper, an initial study of learning from examples is made. After the rule-space of solutions is enlarged from normal formula solutions to all general formula solutions, the following conclusions are got:1. Discussing the change of corresponding rules set, with the change of examples set. 2. There are no solutions when positive-examples set intersets negative-examples set. 3. If the union of positive-examples set and negative-examples set equals to the space which consists of all examples, the rule-solution is unique is unique.4.If the soultions exist,there must be two basic solutions,and these two solutions are maximum and minimun,under the relation of partialorder“=>”.5.the rule set for the opearate ∧,∨ forms a bounded distributive lattice,and the two basic solutions are the upper bound and the lower bound of this lattice respectively.6.GS theorem corresponding to GS algorithm is given.