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Related theorems GIF version |
| Description: Axiom of Quantified Implication. Axiom C4 of [Monk2] p. 105. |
| Ref | Expression |
|---|---|
| ax-5 | ⊢ (∀x(φ → ψ) → (∀xφ → ∀xψ)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | wph | . . . 4 wff φ | |
| 2 | wps | . . . 4 wff ψ | |
| 3 | 1, 2 | wi 3 | . . 3 wff (φ → ψ) |
| 4 | vx | . . 3 set x | |
| 5 | 3, 4 | wal 952 | . 2 wff ∀x(φ → ψ) |
| 6 | 1, 4 | wal 952 | . . 3 wff ∀xφ |
| 7 | 2, 4 | wal 952 | . . 3 wff ∀xψ |
| 8 | 6, 7 | wi 3 | . 2 wff (∀xφ → ∀xψ) |
| 9 | 5, 8 | wi 3 | 1 wff (∀x(φ → ψ) → (∀xφ → ∀xψ)) |
| Colors of variables: wff set class |
| This axiom is referenced by: ax4 970 ax5o 972 |