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Description: Alternate proof of biadani not using biadan . (Contributed by BJ, 4-Mar-2023) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | biadani.1 | ⊢ ( 𝜑 → 𝜓 ) | |
| Assertion | biadaniALT | ⊢ ( ( 𝜓 → ( 𝜑 ↔ 𝜒 ) ) ↔ ( 𝜑 ↔ ( 𝜓 ∧ 𝜒 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | biadani.1 | ⊢ ( 𝜑 → 𝜓 ) | |
| 2 | pm5.32 | ⊢ ( ( 𝜓 → ( 𝜑 ↔ 𝜒 ) ) ↔ ( ( 𝜓 ∧ 𝜑 ) ↔ ( 𝜓 ∧ 𝜒 ) ) ) | |
| 3 | 1 | pm4.71ri | ⊢ ( 𝜑 ↔ ( 𝜓 ∧ 𝜑 ) ) |
| 4 | 3 | bibi1i | ⊢ ( ( 𝜑 ↔ ( 𝜓 ∧ 𝜒 ) ) ↔ ( ( 𝜓 ∧ 𝜑 ) ↔ ( 𝜓 ∧ 𝜒 ) ) ) |
| 5 | 2 4 | bitr4i | ⊢ ( ( 𝜓 → ( 𝜑 ↔ 𝜒 ) ) ↔ ( 𝜑 ↔ ( 𝜓 ∧ 𝜒 ) ) ) |