Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > notnotd | GIF version |
Description: Deduction associated with notnot 624 and notnoti 640. (Contributed by Jarvin Udandy, 2-Sep-2016.) Avoid biconditional. (Revised by Wolf Lammen, 27-Mar-2021.) |
Ref | Expression |
---|---|
notnotd.1 | ⊢ (𝜑 → 𝜓) |
Ref | Expression |
---|---|
notnotd | ⊢ (𝜑 → ¬ ¬ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnotd.1 | . 2 ⊢ (𝜑 → 𝜓) | |
2 | notnot 624 | . 2 ⊢ (𝜓 → ¬ ¬ 𝜓) | |
3 | 1, 2 | syl 14 | 1 ⊢ (𝜑 → ¬ ¬ 𝜓) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-in1 609 ax-in2 610 |
This theorem is referenced by: ismkvnex 7129 exmidonfinlem 7163 mod2eq1n2dvds 11831 pceq0 12268 |
Copyright terms: Public domain | W3C validator |