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(詳細はaxiom in propositional calculus that can be used as a sole wff in a two-axiom formalization of zeroth-order logic. The axiom states the following always has a true truth value. : ((φ ⊼ (χ ⊼ ψ)) ⊼ ((τ ⊼ (τ ⊼ τ)) ⊼ ((θ ⊼ χ) ⊼ ((φ ⊼ θ) ⊼ (φ ⊼ θ))))〔http://us.metamath.org/mpegif/nic-ax.html〕 To utilize this axiom, Nicod made a rule of inference, called Nicod's Modus Ponens. 1. φ 2. (φ ⊼ (χ ⊼ ψ)) ∴ ψ〔http://us.metamath.org/mpegif/nic-mp.html〕 In 1931, Mordechaj Wajsberg found an adequate, and easier-to-work-with alternative. : ((φ ⊼ (ψ ⊼ χ)) ⊼ (((τ ⊼ χ) ⊼ ((φ ⊼ τ) ⊼ (φ ⊼ τ))) ⊼ (φ ⊼ (φ ⊼ ψ))))〔http://www.wolframscience.com/nksonline/page-1151a-text〕 〔 pl:aksjomat Nicoda-Łukasiewicza 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「Nicod's axiom」の詳細全文を読む スポンサード リンク
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