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In predicate logic, generalization (also universal generalization or universal introduction,〔Copi and Cohen〕〔Hurley〕〔Moore and Parker〕 GEN) is a valid inference rule. It states that if has been derived, then can be derived. ==Generalization with hypotheses== The full generalization rule allows for hypotheses to the left of the turnstile, but with restrictions. Assume Γ is a set of formulas, a formula, and has been derived. The generalization rule states that can be derived if ''y'' is not mentioned in Γ and ''x'' does not occur in . These restrictions are necessary for soundness. Without the first restriction, one could conclude from the hypothesis . Without the second restriction, one could make the following deduction: # (Hypothesis) # (Existential instantiation) # (Existential instantiation) # (Faulty universal generalization) This purports to show that which is an unsound deduction. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Universal generalization」の詳細全文を読む スポンサード リンク
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