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Mirrors > Home > MPE Home > Th. List > pm2.13 | Structured version Visualization version GIF version |
Description: Theorem *2.13 of [WhiteheadRussell] p. 101. (Contributed by NM, 3-Jan-2005.) |
Ref | Expression |
---|---|
pm2.13 | ⊢ (𝜑 ∨ ¬ ¬ ¬ 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnot 144 | . 2 ⊢ (¬ 𝜑 → ¬ ¬ ¬ 𝜑) | |
2 | 1 | orri 861 | 1 ⊢ (𝜑 ∨ ¬ ¬ ¬ 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ∨ wo 846 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 210 df-or 847 |
This theorem is referenced by: (None) |
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