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Mirrors > Home > MPE Home > Th. List > unfilem3 | Structured version Visualization version GIF version |
Description: Lemma for proving that the union of two finite sets is finite. (Contributed by NM, 16-Nov-2002.) (Revised by Mario Carneiro, 31-Aug-2015.) |
Ref | Expression |
---|---|
unfilem3 | ⊢ ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → 𝐵 ≈ ((𝐴 +o 𝐵) ∖ 𝐴)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | oveq1 6985 | . . . 4 ⊢ (𝐴 = if(𝐴 ∈ ω, 𝐴, ∅) → (𝐴 +o 𝐵) = (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵)) | |
2 | id 22 | . . . 4 ⊢ (𝐴 = if(𝐴 ∈ ω, 𝐴, ∅) → 𝐴 = if(𝐴 ∈ ω, 𝐴, ∅)) | |
3 | 1, 2 | difeq12d 3992 | . . 3 ⊢ (𝐴 = if(𝐴 ∈ ω, 𝐴, ∅) → ((𝐴 +o 𝐵) ∖ 𝐴) = ((if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵) ∖ if(𝐴 ∈ ω, 𝐴, ∅))) |
4 | 3 | breq2d 4942 | . 2 ⊢ (𝐴 = if(𝐴 ∈ ω, 𝐴, ∅) → (𝐵 ≈ ((𝐴 +o 𝐵) ∖ 𝐴) ↔ 𝐵 ≈ ((if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵) ∖ if(𝐴 ∈ ω, 𝐴, ∅)))) |
5 | id 22 | . . 3 ⊢ (𝐵 = if(𝐵 ∈ ω, 𝐵, ∅) → 𝐵 = if(𝐵 ∈ ω, 𝐵, ∅)) | |
6 | oveq2 6986 | . . . 4 ⊢ (𝐵 = if(𝐵 ∈ ω, 𝐵, ∅) → (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵) = (if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅))) | |
7 | 6 | difeq1d 3990 | . . 3 ⊢ (𝐵 = if(𝐵 ∈ ω, 𝐵, ∅) → ((if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) = ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅))) |
8 | 5, 7 | breq12d 4943 | . 2 ⊢ (𝐵 = if(𝐵 ∈ ω, 𝐵, ∅) → (𝐵 ≈ ((if(𝐴 ∈ ω, 𝐴, ∅) +o 𝐵) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) ↔ if(𝐵 ∈ ω, 𝐵, ∅) ≈ ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅)))) |
9 | peano1 7418 | . . . 4 ⊢ ∅ ∈ ω | |
10 | 9 | elimel 4418 | . . 3 ⊢ if(𝐵 ∈ ω, 𝐵, ∅) ∈ ω |
11 | ovex 7010 | . . . 4 ⊢ (if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∈ V | |
12 | 11 | difexi 5089 | . . 3 ⊢ ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) ∈ V |
13 | 9 | elimel 4418 | . . . 4 ⊢ if(𝐴 ∈ ω, 𝐴, ∅) ∈ ω |
14 | eqid 2778 | . . . 4 ⊢ (𝑥 ∈ if(𝐵 ∈ ω, 𝐵, ∅) ↦ (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝑥)) = (𝑥 ∈ if(𝐵 ∈ ω, 𝐵, ∅) ↦ (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝑥)) | |
15 | 13, 10, 14 | unfilem2 8580 | . . 3 ⊢ (𝑥 ∈ if(𝐵 ∈ ω, 𝐵, ∅) ↦ (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝑥)):if(𝐵 ∈ ω, 𝐵, ∅)–1-1-onto→((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) |
16 | f1oen2g 8325 | . . 3 ⊢ ((if(𝐵 ∈ ω, 𝐵, ∅) ∈ ω ∧ ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) ∈ V ∧ (𝑥 ∈ if(𝐵 ∈ ω, 𝐵, ∅) ↦ (if(𝐴 ∈ ω, 𝐴, ∅) +o 𝑥)):if(𝐵 ∈ ω, 𝐵, ∅)–1-1-onto→((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅))) → if(𝐵 ∈ ω, 𝐵, ∅) ≈ ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅))) | |
17 | 10, 12, 15, 16 | mp3an 1440 | . 2 ⊢ if(𝐵 ∈ ω, 𝐵, ∅) ≈ ((if(𝐴 ∈ ω, 𝐴, ∅) +o if(𝐵 ∈ ω, 𝐵, ∅)) ∖ if(𝐴 ∈ ω, 𝐴, ∅)) |
18 | 4, 8, 17 | dedth2h 4408 | 1 ⊢ ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → 𝐵 ≈ ((𝐴 +o 𝐵) ∖ 𝐴)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 387 = wceq 1507 ∈ wcel 2050 Vcvv 3415 ∖ cdif 3828 ∅c0 4180 ifcif 4351 class class class wbr 4930 ↦ cmpt 5009 –1-1-onto→wf1o 6189 (class class class)co 6978 ωcom 7398 +o coa 7904 ≈ cen 8305 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1758 ax-4 1772 ax-5 1869 ax-6 1928 ax-7 1965 ax-8 2052 ax-9 2059 ax-10 2079 ax-11 2093 ax-12 2106 ax-13 2301 ax-ext 2750 ax-sep 5061 ax-nul 5068 ax-pow 5120 ax-pr 5187 ax-un 7281 |
This theorem depends on definitions: df-bi 199 df-an 388 df-or 834 df-3or 1069 df-3an 1070 df-tru 1510 df-ex 1743 df-nf 1747 df-sb 2016 df-mo 2547 df-eu 2583 df-clab 2759 df-cleq 2771 df-clel 2846 df-nfc 2918 df-ne 2968 df-ral 3093 df-rex 3094 df-reu 3095 df-rab 3097 df-v 3417 df-sbc 3684 df-csb 3789 df-dif 3834 df-un 3836 df-in 3838 df-ss 3845 df-pss 3847 df-nul 4181 df-if 4352 df-pw 4425 df-sn 4443 df-pr 4445 df-tp 4447 df-op 4449 df-uni 4714 df-int 4751 df-iun 4795 df-br 4931 df-opab 4993 df-mpt 5010 df-tr 5032 df-id 5313 df-eprel 5318 df-po 5327 df-so 5328 df-fr 5367 df-we 5369 df-xp 5414 df-rel 5415 df-cnv 5416 df-co 5417 df-dm 5418 df-rn 5419 df-res 5420 df-ima 5421 df-pred 5988 df-ord 6034 df-on 6035 df-lim 6036 df-suc 6037 df-iota 6154 df-fun 6192 df-fn 6193 df-f 6194 df-f1 6195 df-fo 6196 df-f1o 6197 df-fv 6198 df-ov 6981 df-oprab 6982 df-mpo 6983 df-om 7399 df-wrecs 7752 df-recs 7814 df-rdg 7852 df-oadd 7911 df-en 8309 |
This theorem is referenced by: unfi 8582 |
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