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Mirrors > Home > ILE Home > Th. List > elun | GIF version |
Description: Expansion of membership in class union. Theorem 12 of [Suppes] p. 25. (Contributed by NM, 7-Aug-1994.) |
Ref | Expression |
---|---|
elun | ⊢ (𝐴 ∈ (𝐵 ∪ 𝐶) ↔ (𝐴 ∈ 𝐵 ∨ 𝐴 ∈ 𝐶)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex 2748 | . 2 ⊢ (𝐴 ∈ (𝐵 ∪ 𝐶) → 𝐴 ∈ V) | |
2 | elex 2748 | . . 3 ⊢ (𝐴 ∈ 𝐵 → 𝐴 ∈ V) | |
3 | elex 2748 | . . 3 ⊢ (𝐴 ∈ 𝐶 → 𝐴 ∈ V) | |
4 | 2, 3 | jaoi 716 | . 2 ⊢ ((𝐴 ∈ 𝐵 ∨ 𝐴 ∈ 𝐶) → 𝐴 ∈ V) |
5 | eleq1 2240 | . . . 4 ⊢ (𝑥 = 𝐴 → (𝑥 ∈ 𝐵 ↔ 𝐴 ∈ 𝐵)) | |
6 | eleq1 2240 | . . . 4 ⊢ (𝑥 = 𝐴 → (𝑥 ∈ 𝐶 ↔ 𝐴 ∈ 𝐶)) | |
7 | 5, 6 | orbi12d 793 | . . 3 ⊢ (𝑥 = 𝐴 → ((𝑥 ∈ 𝐵 ∨ 𝑥 ∈ 𝐶) ↔ (𝐴 ∈ 𝐵 ∨ 𝐴 ∈ 𝐶))) |
8 | df-un 3133 | . . 3 ⊢ (𝐵 ∪ 𝐶) = {𝑥 ∣ (𝑥 ∈ 𝐵 ∨ 𝑥 ∈ 𝐶)} | |
9 | 7, 8 | elab2g 2884 | . 2 ⊢ (𝐴 ∈ V → (𝐴 ∈ (𝐵 ∪ 𝐶) ↔ (𝐴 ∈ 𝐵 ∨ 𝐴 ∈ 𝐶))) |
10 | 1, 4, 9 | pm5.21nii 704 | 1 ⊢ (𝐴 ∈ (𝐵 ∪ 𝐶) ↔ (𝐴 ∈ 𝐵 ∨ 𝐴 ∈ 𝐶)) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 105 ∨ wo 708 = wceq 1353 ∈ wcel 2148 Vcvv 2737 ∪ cun 3127 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 709 ax-5 1447 ax-7 1448 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-10 1505 ax-11 1506 ax-i12 1507 ax-bndl 1509 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-i5r 1535 ax-ext 2159 |
This theorem depends on definitions: df-bi 117 df-tru 1356 df-nf 1461 df-sb 1763 df-clab 2164 df-cleq 2170 df-clel 2173 df-nfc 2308 df-v 2739 df-un 3133 |
This theorem is referenced by: uneqri 3277 uncom 3279 uneq1 3282 unass 3292 ssun1 3298 unss1 3304 ssequn1 3305 unss 3309 rexun 3315 ralunb 3316 unssdif 3370 unssin 3374 inssun 3375 indi 3382 undi 3383 difundi 3387 difindiss 3389 undif3ss 3396 symdifxor 3401 rabun2 3414 reuun2 3418 undif4 3485 ssundifim 3506 dcun 3533 dfpr2 3611 eltpg 3637 pwprss 3805 pwtpss 3806 uniun 3828 intun 3875 iunun 3965 iunxun 3966 iinuniss 3969 brun 4054 undifexmid 4193 exmidundif 4206 exmidundifim 4207 exmid1stab 4208 pwunss 4283 elsuci 4403 elsucg 4404 elsuc2g 4405 ordsucim 4499 sucprcreg 4548 opthprc 4677 xpundi 4682 xpundir 4683 funun 5260 mptun 5347 unpreima 5641 reldmtpos 6253 dftpos4 6263 tpostpos 6264 onunsnss 6915 unfidisj 6920 undifdcss 6921 fidcenumlemrks 6951 djulclb 7053 eldju 7066 eldju2ndl 7070 eldju2ndr 7071 ctssdccl 7109 pw1nel3 7229 sucpw1nel3 7231 elnn0 9177 un0addcl 9208 un0mulcl 9209 elxnn0 9240 ltxr 9774 elxr 9775 fzsplit2 10049 elfzp1 10071 uzsplit 10091 elfzp12 10098 fz01or 10110 fzosplit 10176 fzouzsplit 10178 elfzonlteqm1 10209 fzosplitsni 10234 hashinfuni 10756 hashennnuni 10758 hashunlem 10783 zfz1isolemiso 10818 summodclem3 11387 fsumsplit 11414 fsumsplitsn 11417 sumsplitdc 11439 fprodsplitdc 11603 fprodsplit 11604 fprodunsn 11611 fprodsplitsn 11640 nnnn0modprm0 12254 prm23lt5 12262 reopnap 14008 lgsdir2 14404 2lgsoddprmlem3 14429 djulclALT 14523 djurclALT 14524 bj-charfun 14529 bj-nntrans 14673 bj-nnelirr 14675 |
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