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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 36218 and ax-bj-bun 36222. Contrary to bj-prex 36225, this proof is intuitionistically valid and does not require ax-nul 5306. (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 4631 | . 2 ⊢ {𝐴, 𝐵} = ({𝐴} ∪ {𝐵}) | |
2 | bj-snexg 36219 | . . 3 ⊢ (𝐴 ∈ 𝑉 → {𝐴} ∈ V) | |
3 | bj-snexg 36219 | . . 3 ⊢ (𝐵 ∈ 𝑊 → {𝐵} ∈ V) | |
4 | bj-unexg 36223 | . . 3 ⊢ (({𝐴} ∈ V ∧ {𝐵} ∈ V) → ({𝐴} ∪ {𝐵}) ∈ V) | |
5 | 2, 3, 4 | syl2an 595 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ({𝐴} ∪ {𝐵}) ∈ V) |
6 | 1, 5 | eqeltrid 2836 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 ∈ wcel 2105 Vcvv 3473 ∪ cun 3946 {csn 4628 {cpr 4630 |
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 1912 ax-6 1970 ax-7 2010 ax-8 2107 ax-9 2115 ax-12 2170 ax-ext 2702 ax-bj-sn 36218 ax-bj-bun 36222 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-tru 1543 df-ex 1781 df-sb 2067 df-clab 2709 df-cleq 2723 df-clel 2809 df-v 3475 df-un 3953 df-sn 4629 df-pr 4631 |
This theorem is referenced by: (None) |
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