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Related theorems GIF version |
| Description: Formula-building rule for restricted existential quantifier (deduction rule). |
| Ref | Expression |
|---|---|
| ralbidv.1 | ⊢ (φ → (ψ ↔ χ)) |
| Ref | Expression |
|---|---|
| rexbidv | ⊢ (φ → (∃x ∈ A ψ ↔ ∃x ∈ A χ)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax-17 1007 | . 2 ⊢ (φ → ∀xφ) | |
| 2 | ralbidv.1 | . 2 ⊢ (φ → (ψ ↔ χ)) | |
| 3 | 1, 2 | rexbid 1708 | 1 ⊢ (φ → (∃x ∈ A ψ ↔ ∃x ∈ A χ)) |