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Description: Introduce a left anti-conjunct to both sides of a logical equivalence. (Contributed by SF, 2-Jan-2018)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | nanbid.1 | ⊢ ( 𝜑 → ( 𝜓 ↔ 𝜒 ) ) | |
| Assertion | nanbi2d | ⊢ ( 𝜑 → ( ( 𝜃 ⊼ 𝜓 ) ↔ ( 𝜃 ⊼ 𝜒 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nanbid.1 | ⊢ ( 𝜑 → ( 𝜓 ↔ 𝜒 ) ) | |
| 2 | nanbi2 | ⊢ ( ( 𝜓 ↔ 𝜒 ) → ( ( 𝜃 ⊼ 𝜓 ) ↔ ( 𝜃 ⊼ 𝜒 ) ) ) | |
| 3 | 1 2 | syl | ⊢ ( 𝜑 → ( ( 𝜃 ⊼ 𝜓 ) ↔ ( 𝜃 ⊼ 𝜒 ) ) ) |