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| Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-ntrufal | Structured version Visualization version GIF version | ||
| Description: The negation of a theorem is equivalent to false. This can shorten dfnul2 4336. (Contributed by BJ, 5-Oct-2024.) | 
| Ref | Expression | 
|---|---|
| bj-ntrufal.1 | ⊢ 𝜑 | 
| Ref | Expression | 
|---|---|
| bj-ntrufal | ⊢ (¬ 𝜑 ↔ ⊥) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bj-ntrufal.1 | . . 3 ⊢ 𝜑 | |
| 2 | 1 | notnoti 143 | . 2 ⊢ ¬ ¬ 𝜑 | 
| 3 | 2 | bifal 1556 | 1 ⊢ (¬ 𝜑 ↔ ⊥) | 
| Colors of variables: wff setvar class | 
| Syntax hints: ¬ wn 3 ↔ wb 206 ⊥wfal 1552 | 
| 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 207 df-tru 1543 df-fal 1553 | 
| This theorem is referenced by: (None) | 
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