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| Mirrors > Home > MPE Home > Th. List > Mathboxes > nfexhe | Structured version Visualization version GIF version | ||
| Description: Version of nfex 2327 with the existential dual to the 'h' hypothesis, avoiding ax-12 2182. (Contributed by SN, 11-Feb-2026.) |
| Ref | Expression |
|---|---|
| nfexhe.1 | ⊢ (∃𝑥𝜑 → 𝜑) |
| Ref | Expression |
|---|---|
| nfexhe | ⊢ Ⅎ𝑥∃𝑦𝜑 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hbe1 2148 | . . 3 ⊢ (∃𝑥∃𝑦𝜑 → ∀𝑥∃𝑥∃𝑦𝜑) | |
| 2 | excomim 2168 | . . . 4 ⊢ (∃𝑥∃𝑦𝜑 → ∃𝑦∃𝑥𝜑) | |
| 3 | nfexhe.1 | . . . . 5 ⊢ (∃𝑥𝜑 → 𝜑) | |
| 4 | 3 | eximi 1836 | . . . 4 ⊢ (∃𝑦∃𝑥𝜑 → ∃𝑦𝜑) |
| 5 | 2, 4 | syl 17 | . . 3 ⊢ (∃𝑥∃𝑦𝜑 → ∃𝑦𝜑) |
| 6 | 1, 5 | alrimih 1825 | . 2 ⊢ (∃𝑥∃𝑦𝜑 → ∀𝑥∃𝑦𝜑) |
| 7 | 6 | nfi 1789 | 1 ⊢ Ⅎ𝑥∃𝑦𝜑 |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ∃wex 1780 Ⅎwnf 1784 |
| 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-10 2146 ax-11 2162 |
| This theorem depends on definitions: df-bi 207 df-ex 1781 df-nf 1785 |
| This theorem is referenced by: nfexa2 42321 |
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