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Mirrors > Home > MPE Home > Th. List > Mathboxes > axfrege41 | Structured version Visualization version GIF version |
Description: Identical to notnot 135. Axiom 41 of [Frege1879] p. 47. (Contributed by RP, 24-Dec-2019.) |
Ref | Expression |
---|---|
axfrege41 | ⊢ (𝜑 → ¬ ¬ 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnot 135 | 1 ⊢ (𝜑 → ¬ ¬ 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem is referenced by: (None) |
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