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Mirrors > Home > ILE Home > Th. List > ax10o | GIF version |
Description: Show that ax-10o 1644 can be derived from ax-10 1436. An open problem is
whether this theorem can be derived from ax-10 1436 and the others when
ax-11 1437 is replaced with ax-11o 1744. See theorem ax10 1645
for the
rederivation of ax-10 1436 from ax10o 1643.
Normally, ax10o 1643 should be used rather than ax-10o 1644, except by theorems specifically studying the latter's properties. (Contributed by NM, 16-May-2008.) |
Ref | Expression |
---|---|
ax10o | ⊢ (∀𝑥 𝑥 = 𝑦 → (∀𝑥𝜑 → ∀𝑦𝜑)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-10 1436 | . 2 ⊢ (∀𝑥 𝑥 = 𝑦 → ∀𝑦 𝑦 = 𝑥) | |
2 | ax-11 1437 | . . . 4 ⊢ (𝑦 = 𝑥 → (∀𝑥𝜑 → ∀𝑦(𝑦 = 𝑥 → 𝜑))) | |
3 | 2 | equcoms 1634 | . . 3 ⊢ (𝑥 = 𝑦 → (∀𝑥𝜑 → ∀𝑦(𝑦 = 𝑥 → 𝜑))) |
4 | 3 | sps 1470 | . 2 ⊢ (∀𝑥 𝑥 = 𝑦 → (∀𝑥𝜑 → ∀𝑦(𝑦 = 𝑥 → 𝜑))) |
5 | pm2.27 39 | . . 3 ⊢ (𝑦 = 𝑥 → ((𝑦 = 𝑥 → 𝜑) → 𝜑)) | |
6 | 5 | al2imi 1387 | . 2 ⊢ (∀𝑦 𝑦 = 𝑥 → (∀𝑦(𝑦 = 𝑥 → 𝜑) → ∀𝑦𝜑)) |
7 | 1, 4, 6 | sylsyld 57 | 1 ⊢ (∀𝑥 𝑥 = 𝑦 → (∀𝑥𝜑 → ∀𝑦𝜑)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∀wal 1282 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-5 1376 ax-gen 1378 ax-ie2 1423 ax-8 1435 ax-10 1436 ax-11 1437 ax-4 1440 ax-17 1459 ax-i9 1463 |
This theorem depends on definitions: df-bi 115 |
This theorem is referenced by: hbae 1646 dral1 1658 |
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