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Mirrors > Home > MPE Home > Th. List > hbsb2ALT | Structured version Visualization version GIF version |
Description: Alternate version of hbsb2 2521. (Contributed by NM, 14-May-1993.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
dfsb1.p3 | ⊢ (𝜃 ↔ ((𝑥 = 𝑦 → 𝜑) ∧ ∃𝑥(𝑥 = 𝑦 ∧ 𝜑))) |
Ref | Expression |
---|---|
hbsb2ALT | ⊢ (¬ ∀𝑥 𝑥 = 𝑦 → (𝜃 → ∀𝑥𝜃)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfsb1.p3 | . . 3 ⊢ (𝜃 ↔ ((𝑥 = 𝑦 → 𝜑) ∧ ∃𝑥(𝑥 = 𝑦 ∧ 𝜑))) | |
2 | 1 | sb4ALT 2588 | . 2 ⊢ (¬ ∀𝑥 𝑥 = 𝑦 → (𝜃 → ∀𝑥(𝑥 = 𝑦 → 𝜑))) |
3 | 1 | sb2ALT 2587 | . . 3 ⊢ (∀𝑥(𝑥 = 𝑦 → 𝜑) → 𝜃) |
4 | 3 | axc4i 2341 | . 2 ⊢ (∀𝑥(𝑥 = 𝑦 → 𝜑) → ∀𝑥𝜃) |
5 | 2, 4 | syl6 35 | 1 ⊢ (¬ ∀𝑥 𝑥 = 𝑦 → (𝜃 → ∀𝑥𝜃)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 208 ∧ wa 398 ∀wal 1535 ∃wex 1780 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-10 2145 ax-12 2177 ax-13 2390 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-ex 1781 df-nf 1785 |
This theorem is referenced by: nfsb2ALT 2600 |
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