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Mirrors > Home > MPE Home > Th. List > uniprg | Structured version Visualization version GIF version |
Description: The union of a pair is the union of its members. Proposition 5.7 of [TakeutiZaring] p. 16. (Contributed by NM, 25-Aug-2006.) |
Ref | Expression |
---|---|
uniprg | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∪ {𝐴, 𝐵} = (𝐴 ∪ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | preq1 4486 | . . . 4 ⊢ (𝑥 = 𝐴 → {𝑥, 𝑦} = {𝐴, 𝑦}) | |
2 | 1 | unieqd 4668 | . . 3 ⊢ (𝑥 = 𝐴 → ∪ {𝑥, 𝑦} = ∪ {𝐴, 𝑦}) |
3 | uneq1 3987 | . . 3 ⊢ (𝑥 = 𝐴 → (𝑥 ∪ 𝑦) = (𝐴 ∪ 𝑦)) | |
4 | 2, 3 | eqeq12d 2840 | . 2 ⊢ (𝑥 = 𝐴 → (∪ {𝑥, 𝑦} = (𝑥 ∪ 𝑦) ↔ ∪ {𝐴, 𝑦} = (𝐴 ∪ 𝑦))) |
5 | preq2 4487 | . . . 4 ⊢ (𝑦 = 𝐵 → {𝐴, 𝑦} = {𝐴, 𝐵}) | |
6 | 5 | unieqd 4668 | . . 3 ⊢ (𝑦 = 𝐵 → ∪ {𝐴, 𝑦} = ∪ {𝐴, 𝐵}) |
7 | uneq2 3988 | . . 3 ⊢ (𝑦 = 𝐵 → (𝐴 ∪ 𝑦) = (𝐴 ∪ 𝐵)) | |
8 | 6, 7 | eqeq12d 2840 | . 2 ⊢ (𝑦 = 𝐵 → (∪ {𝐴, 𝑦} = (𝐴 ∪ 𝑦) ↔ ∪ {𝐴, 𝐵} = (𝐴 ∪ 𝐵))) |
9 | vex 3417 | . . 3 ⊢ 𝑥 ∈ V | |
10 | vex 3417 | . . 3 ⊢ 𝑦 ∈ V | |
11 | 9, 10 | unipr 4671 | . 2 ⊢ ∪ {𝑥, 𝑦} = (𝑥 ∪ 𝑦) |
12 | 4, 8, 11 | vtocl2g 3486 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∪ {𝐴, 𝐵} = (𝐴 ∪ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 386 = wceq 1658 ∈ wcel 2166 ∪ cun 3796 {cpr 4399 ∪ cuni 4658 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1896 ax-4 1910 ax-5 2011 ax-6 2077 ax-7 2114 ax-9 2175 ax-10 2194 ax-11 2209 ax-12 2222 ax-ext 2803 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 881 df-tru 1662 df-ex 1881 df-nf 1885 df-sb 2070 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-rex 3123 df-v 3416 df-un 3803 df-sn 4398 df-pr 4400 df-uni 4659 |
This theorem is referenced by: unisng 4673 wunun 9847 tskun 9923 gruun 9943 mrcun 16635 unopn 21078 indistopon 21176 unconn 21603 limcun 24058 sshjval3 28768 prsiga 30739 unelsiga 30742 unelldsys 30766 measxun2 30818 measssd 30823 carsgsigalem 30922 carsgclctun 30928 pmeasmono 30931 probun 31027 indispconn 31762 kelac2 38478 fourierdlem70 41187 fourierdlem71 41188 saluncl 41328 prsal 41329 meadjun 41470 omeunle 41524 |
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