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Mirrors > Home > ILE Home > Th. List > Mathboxes > bj-notbii | GIF version |
Description: Inference associated with bj-notbi 10045. (Contributed by BJ, 27-Jan-2020.) (Proof modification is discouraged.) |
Ref | Expression |
---|---|
bj-notbii.1 | ⊢ (𝜑 ↔ 𝜓) |
Ref | Expression |
---|---|
bj-notbii | ⊢ (¬ 𝜑 ↔ ¬ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bj-notbii.1 | . 2 ⊢ (𝜑 ↔ 𝜓) | |
2 | bj-notbi 10045 | . 2 ⊢ ((𝜑 ↔ 𝜓) → (¬ 𝜑 ↔ ¬ 𝜓)) | |
3 | 1, 2 | ax-mp 7 | 1 ⊢ (¬ 𝜑 ↔ ¬ 𝜓) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 ↔ wb 98 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 |
This theorem depends on definitions: df-bi 110 |
This theorem is referenced by: (None) |
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