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| Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-prexg | Structured version Visualization version GIF version | ||
| Description: Existence of unordered pairs formed on sets, proved from ax-bj-sn 37328 and ax-bj-bun 37332. Contrary to bj-prex 37335, this proof is intuitionistically valid and does not require ax-nul 5230. (Contributed by BJ, 12-Jan-2025.) (Proof modification is discouraged.) |
| Ref | Expression |
|---|---|
| bj-prexg | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-pr 4560 | . 2 ⊢ {𝐴, 𝐵} = ({𝐴} ∪ {𝐵}) | |
| 2 | bj-snexg 37329 | . . 3 ⊢ (𝐴 ∈ 𝑉 → {𝐴} ∈ V) | |
| 3 | bj-snexg 37329 | . . 3 ⊢ (𝐵 ∈ 𝑊 → {𝐵} ∈ V) | |
| 4 | bj-unexg 37333 | . . 3 ⊢ (({𝐴} ∈ V ∧ {𝐵} ∈ V) → ({𝐴} ∪ {𝐵}) ∈ V) | |
| 5 | 2, 3, 4 | syl2an 597 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ({𝐴} ∪ {𝐵}) ∈ V) |
| 6 | 1, 5 | eqeltrid 2839 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ∧ wa 395 ∈ wcel 2114 Vcvv 3427 ∪ cun 3883 {csn 4557 {cpr 4559 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1912 ax-6 1969 ax-7 2010 ax-8 2116 ax-9 2124 ax-12 2184 ax-ext 2707 ax-bj-sn 37328 ax-bj-bun 37332 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-tru 1545 df-ex 1782 df-sb 2069 df-clab 2714 df-cleq 2727 df-clel 2810 df-v 3429 df-un 3890 df-sn 4558 df-pr 4560 |
| This theorem is referenced by: (None) |
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