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Mirrors > Home > MPE Home > Th. List > eeor | Structured version Visualization version GIF version |
Description: Distribute existential quantifiers. (Contributed by NM, 8-Aug-1994.) Avoid ax-10 2138. (Revised by Gino Giotto, 21-Nov-2024.) |
Ref | Expression |
---|---|
eeor.1 | ⊢ Ⅎ𝑦𝜑 |
eeor.2 | ⊢ Ⅎ𝑥𝜓 |
Ref | Expression |
---|---|
eeor | ⊢ (∃𝑥∃𝑦(𝜑 ∨ 𝜓) ↔ (∃𝑥𝜑 ∨ ∃𝑦𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 19.43 1886 | . . 3 ⊢ (∃𝑦(𝜑 ∨ 𝜓) ↔ (∃𝑦𝜑 ∨ ∃𝑦𝜓)) | |
2 | 1 | exbii 1851 | . 2 ⊢ (∃𝑥∃𝑦(𝜑 ∨ 𝜓) ↔ ∃𝑥(∃𝑦𝜑 ∨ ∃𝑦𝜓)) |
3 | 19.43 1886 | . . 3 ⊢ (∃𝑥(∃𝑦𝜑 ∨ ∃𝑦𝜓) ↔ (∃𝑥∃𝑦𝜑 ∨ ∃𝑥∃𝑦𝜓)) | |
4 | eeor.1 | . . . . . 6 ⊢ Ⅎ𝑦𝜑 | |
5 | 4 | 19.9 2199 | . . . . 5 ⊢ (∃𝑦𝜑 ↔ 𝜑) |
6 | 5 | exbii 1851 | . . . 4 ⊢ (∃𝑥∃𝑦𝜑 ↔ ∃𝑥𝜑) |
7 | excom 2163 | . . . . 5 ⊢ (∃𝑥∃𝑦𝜓 ↔ ∃𝑦∃𝑥𝜓) | |
8 | eeor.2 | . . . . . . 7 ⊢ Ⅎ𝑥𝜓 | |
9 | 8 | 19.9 2199 | . . . . . 6 ⊢ (∃𝑥𝜓 ↔ 𝜓) |
10 | 9 | exbii 1851 | . . . . 5 ⊢ (∃𝑦∃𝑥𝜓 ↔ ∃𝑦𝜓) |
11 | 7, 10 | bitri 275 | . . . 4 ⊢ (∃𝑥∃𝑦𝜓 ↔ ∃𝑦𝜓) |
12 | 6, 11 | orbi12i 914 | . . 3 ⊢ ((∃𝑥∃𝑦𝜑 ∨ ∃𝑥∃𝑦𝜓) ↔ (∃𝑥𝜑 ∨ ∃𝑦𝜓)) |
13 | 3, 12 | bitri 275 | . 2 ⊢ (∃𝑥(∃𝑦𝜑 ∨ ∃𝑦𝜓) ↔ (∃𝑥𝜑 ∨ ∃𝑦𝜓)) |
14 | 2, 13 | bitri 275 | 1 ⊢ (∃𝑥∃𝑦(𝜑 ∨ 𝜓) ↔ (∃𝑥𝜑 ∨ ∃𝑦𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 205 ∨ wo 846 ∃wex 1782 Ⅎwnf 1786 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-11 2155 ax-12 2172 |
This theorem depends on definitions: df-bi 206 df-or 847 df-ex 1783 df-nf 1787 |
This theorem is referenced by: (None) |
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