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Mirrors > Home > ILE Home > Th. List > unexg | GIF version |
Description: A union of two sets is a set. Corollary 5.8 of [TakeutiZaring] p. 16. (Contributed by NM, 18-Sep-2006.) |
Ref | Expression |
---|---|
unexg | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴 ∪ 𝐵) ∈ V) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex 2671 | . 2 ⊢ (𝐴 ∈ 𝑉 → 𝐴 ∈ V) | |
2 | elex 2671 | . 2 ⊢ (𝐵 ∈ 𝑊 → 𝐵 ∈ V) | |
3 | unexb 4333 | . . 3 ⊢ ((𝐴 ∈ V ∧ 𝐵 ∈ V) ↔ (𝐴 ∪ 𝐵) ∈ V) | |
4 | 3 | biimpi 119 | . 2 ⊢ ((𝐴 ∈ V ∧ 𝐵 ∈ V) → (𝐴 ∪ 𝐵) ∈ V) |
5 | 1, 2, 4 | syl2an 287 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴 ∪ 𝐵) ∈ V) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ∈ wcel 1465 Vcvv 2660 ∪ cun 3039 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 683 ax-5 1408 ax-7 1409 ax-gen 1410 ax-ie1 1454 ax-ie2 1455 ax-8 1467 ax-10 1468 ax-11 1469 ax-i12 1470 ax-bndl 1471 ax-4 1472 ax-13 1476 ax-14 1477 ax-17 1491 ax-i9 1495 ax-ial 1499 ax-i5r 1500 ax-ext 2099 ax-sep 4016 ax-pr 4101 ax-un 4325 |
This theorem depends on definitions: df-bi 116 df-tru 1319 df-nf 1422 df-sb 1721 df-clab 2104 df-cleq 2110 df-clel 2113 df-nfc 2247 df-rex 2399 df-v 2662 df-un 3045 df-in 3047 df-ss 3054 df-sn 3503 df-pr 3504 df-uni 3707 |
This theorem is referenced by: tpexg 4335 eldifpw 4368 xpexg 4623 tposexg 6123 tfrlemisucaccv 6190 tfrlemibxssdm 6192 tfrlemibfn 6193 tfr1onlemsucaccv 6206 tfr1onlembxssdm 6208 tfr1onlembfn 6209 tfrcllemsucaccv 6219 tfrcllembxssdm 6221 tfrcllembfn 6222 rdgtfr 6239 rdgruledefgg 6240 rdgivallem 6246 djuex 6896 zfz1isolem1 10551 ennnfonelemp1 11846 setsvalg 11916 setsex 11918 setsslid 11936 strleund 11974 |
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