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Mirrors > Home > ILE Home > Th. List > sylbb | GIF version |
Description: A mixed syllogism inference from two biconditionals. (Contributed by BJ, 30-Mar-2019.) |
Ref | Expression |
---|---|
sylbb.1 | ⊢ (𝜑 ↔ 𝜓) |
sylbb.2 | ⊢ (𝜓 ↔ 𝜒) |
Ref | Expression |
---|---|
sylbb | ⊢ (𝜑 → 𝜒) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sylbb.1 | . 2 ⊢ (𝜑 ↔ 𝜓) | |
2 | sylbb.2 | . . 3 ⊢ (𝜓 ↔ 𝜒) | |
3 | 2 | biimpi 118 | . 2 ⊢ (𝜓 → 𝜒) |
4 | 1, 3 | sylbi 119 | 1 ⊢ (𝜑 → 𝜒) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 103 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 |
This theorem depends on definitions: df-bi 115 |
This theorem is referenced by: (None) |
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