Based on the truth degree, the type of logic inequality τ(A X ) 3 α plays an important role in the study of the approximate reasoning in the two-valued propositional logic system L. According to several necessary and sufficient conditions for the solution of logic inequality τ(A X ) 3 α in F(Sn), the solution set expression of this kind of logic inequality is obtained, and the classification theory is suggested under the relations either equality of truth degree or logic equivalent. Meanwhile, the structura...