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| Mirrors > Home > ILE Home > Th. List > ax-5 | GIF version | ||
| Description: Axiom of Quantified Implication. Axiom C4 of [Monk2] p. 105. (Contributed by NM, 5-Aug-1993.) |
| 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 4 | . . 3 wff (𝜑 → 𝜓) |
| 4 | vx | . . 3 setvar 𝑥 | |
| 5 | 3, 4 | wal 1362 | . 2 wff ∀𝑥(𝜑 → 𝜓) |
| 6 | 1, 4 | wal 1362 | . . 3 wff ∀𝑥𝜑 |
| 7 | 2, 4 | wal 1362 | . . 3 wff ∀𝑥𝜓 |
| 8 | 6, 7 | wi 4 | . 2 wff (∀𝑥𝜑 → ∀𝑥𝜓) |
| 9 | 5, 8 | wi 4 | 1 wff (∀𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → ∀𝑥𝜓)) |
| Colors of variables: wff set class |
| This axiom is referenced by: alimi 1469 alim 1471 nfrimi 1539 a5i 1557 nfal 1590 |
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