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Description: Equality deduction for a binary relation. (Contributed by NM, 8-Feb-1996) (Proof shortened by Andrew Salmon, 9-Jul-2011)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | breq1d.1 | ⊢ ( 𝜑 → 𝐴 = 𝐵 ) | |
| breq12d.2 | ⊢ ( 𝜑 → 𝐶 = 𝐷 ) | ||
| Assertion | breq12d | ⊢ ( 𝜑 → ( 𝐴 𝑅 𝐶 ↔ 𝐵 𝑅 𝐷 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | breq1d.1 | ⊢ ( 𝜑 → 𝐴 = 𝐵 ) | |
| 2 | breq12d.2 | ⊢ ( 𝜑 → 𝐶 = 𝐷 ) | |
| 3 | breq12 | ⊢ ( ( 𝐴 = 𝐵 ∧ 𝐶 = 𝐷 ) → ( 𝐴 𝑅 𝐶 ↔ 𝐵 𝑅 𝐷 ) ) | |
| 4 | 1 2 3 | syl2anc | ⊢ ( 𝜑 → ( 𝐴 𝑅 𝐶 ↔ 𝐵 𝑅 𝐷 ) ) |