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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 36999 and ax-bj-bun 37003. Contrary to bj-prex 37006, this proof is intuitionistically valid and does not require ax-nul 5324. (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 4651 | . 2 ⊢ {𝐴, 𝐵} = ({𝐴} ∪ {𝐵}) | |
2 | bj-snexg 37000 | . . 3 ⊢ (𝐴 ∈ 𝑉 → {𝐴} ∈ V) | |
3 | bj-snexg 37000 | . . 3 ⊢ (𝐵 ∈ 𝑊 → {𝐵} ∈ V) | |
4 | bj-unexg 37004 | . . 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 2848 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 ∈ wcel 2108 Vcvv 3488 ∪ cun 3974 {csn 4648 {cpr 4650 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1793 ax-4 1807 ax-5 1909 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-12 2178 ax-ext 2711 ax-bj-sn 36999 ax-bj-bun 37003 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 847 df-tru 1540 df-ex 1778 df-sb 2065 df-clab 2718 df-cleq 2732 df-clel 2819 df-v 3490 df-un 3981 df-sn 4649 df-pr 4651 |
This theorem is referenced by: (None) |
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