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Description: Equivalent formulas yield equal restricted class abstractions (inference form). (Contributed by NM, 22-May-1999) (Proof shortened by Wolf Lammen, 12-Jan-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | rabbiia.1 | ⊢ ( 𝑥 ∈ 𝐴 → ( 𝜑 ↔ 𝜓 ) ) | |
| Assertion | rabbiia | ⊢ { 𝑥 ∈ 𝐴 ∣ 𝜑 } = { 𝑥 ∈ 𝐴 ∣ 𝜓 } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | rabbiia.1 | ⊢ ( 𝑥 ∈ 𝐴 → ( 𝜑 ↔ 𝜓 ) ) | |
| 2 | 1 | pm5.32i | ⊢ ( ( 𝑥 ∈ 𝐴 ∧ 𝜑 ) ↔ ( 𝑥 ∈ 𝐴 ∧ 𝜓 ) ) |
| 3 | 2 | rabbia2 | ⊢ { 𝑥 ∈ 𝐴 ∣ 𝜑 } = { 𝑥 ∈ 𝐴 ∣ 𝜓 } |