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Mirrors > Home > MPE Home > Th. List > cusgrfilem3 | Structured version Visualization version GIF version |
Description: Lemma 3 for cusgrfi 27248. (Contributed by Alexander van der Vekens, 13-Jan-2018.) (Revised by AV, 11-Nov-2020.) |
Ref | Expression |
---|---|
cusgrfi.v | ⊢ 𝑉 = (Vtx‘𝐺) |
cusgrfi.p | ⊢ 𝑃 = {𝑥 ∈ 𝒫 𝑉 ∣ ∃𝑎 ∈ 𝑉 (𝑎 ≠ 𝑁 ∧ 𝑥 = {𝑎, 𝑁})} |
cusgrfi.f | ⊢ 𝐹 = (𝑥 ∈ (𝑉 ∖ {𝑁}) ↦ {𝑥, 𝑁}) |
Ref | Expression |
---|---|
cusgrfilem3 | ⊢ (𝑁 ∈ 𝑉 → (𝑉 ∈ Fin ↔ 𝑃 ∈ Fin)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | diffi 8734 | . . 3 ⊢ (𝑉 ∈ Fin → (𝑉 ∖ {𝑁}) ∈ Fin) | |
2 | simpr 488 | . . . . . 6 ⊢ ((𝑁 ∈ 𝑉 ∧ ¬ 𝑉 ∈ Fin) → ¬ 𝑉 ∈ Fin) | |
3 | snfi 8577 | . . . . . 6 ⊢ {𝑁} ∈ Fin | |
4 | difinf 8772 | . . . . . 6 ⊢ ((¬ 𝑉 ∈ Fin ∧ {𝑁} ∈ Fin) → ¬ (𝑉 ∖ {𝑁}) ∈ Fin) | |
5 | 2, 3, 4 | sylancl 589 | . . . . 5 ⊢ ((𝑁 ∈ 𝑉 ∧ ¬ 𝑉 ∈ Fin) → ¬ (𝑉 ∖ {𝑁}) ∈ Fin) |
6 | 5 | ex 416 | . . . 4 ⊢ (𝑁 ∈ 𝑉 → (¬ 𝑉 ∈ Fin → ¬ (𝑉 ∖ {𝑁}) ∈ Fin)) |
7 | 6 | con4d 115 | . . 3 ⊢ (𝑁 ∈ 𝑉 → ((𝑉 ∖ {𝑁}) ∈ Fin → 𝑉 ∈ Fin)) |
8 | 1, 7 | impbid2 229 | . 2 ⊢ (𝑁 ∈ 𝑉 → (𝑉 ∈ Fin ↔ (𝑉 ∖ {𝑁}) ∈ Fin)) |
9 | cusgrfi.f | . . . . . 6 ⊢ 𝐹 = (𝑥 ∈ (𝑉 ∖ {𝑁}) ↦ {𝑥, 𝑁}) | |
10 | cusgrfi.v | . . . . . . . . 9 ⊢ 𝑉 = (Vtx‘𝐺) | |
11 | 10 | fvexi 6659 | . . . . . . . 8 ⊢ 𝑉 ∈ V |
12 | 11 | difexi 5196 | . . . . . . 7 ⊢ (𝑉 ∖ {𝑁}) ∈ V |
13 | mptexg 6961 | . . . . . . 7 ⊢ ((𝑉 ∖ {𝑁}) ∈ V → (𝑥 ∈ (𝑉 ∖ {𝑁}) ↦ {𝑥, 𝑁}) ∈ V) | |
14 | 12, 13 | mp1i 13 | . . . . . 6 ⊢ (𝑁 ∈ 𝑉 → (𝑥 ∈ (𝑉 ∖ {𝑁}) ↦ {𝑥, 𝑁}) ∈ V) |
15 | 9, 14 | eqeltrid 2894 | . . . . 5 ⊢ (𝑁 ∈ 𝑉 → 𝐹 ∈ V) |
16 | cusgrfi.p | . . . . . 6 ⊢ 𝑃 = {𝑥 ∈ 𝒫 𝑉 ∣ ∃𝑎 ∈ 𝑉 (𝑎 ≠ 𝑁 ∧ 𝑥 = {𝑎, 𝑁})} | |
17 | 10, 16, 9 | cusgrfilem2 27246 | . . . . 5 ⊢ (𝑁 ∈ 𝑉 → 𝐹:(𝑉 ∖ {𝑁})–1-1-onto→𝑃) |
18 | f1oeq1 6579 | . . . . 5 ⊢ (𝑓 = 𝐹 → (𝑓:(𝑉 ∖ {𝑁})–1-1-onto→𝑃 ↔ 𝐹:(𝑉 ∖ {𝑁})–1-1-onto→𝑃)) | |
19 | 15, 17, 18 | spcedv 3547 | . . . 4 ⊢ (𝑁 ∈ 𝑉 → ∃𝑓 𝑓:(𝑉 ∖ {𝑁})–1-1-onto→𝑃) |
20 | bren 8501 | . . . 4 ⊢ ((𝑉 ∖ {𝑁}) ≈ 𝑃 ↔ ∃𝑓 𝑓:(𝑉 ∖ {𝑁})–1-1-onto→𝑃) | |
21 | 19, 20 | sylibr 237 | . . 3 ⊢ (𝑁 ∈ 𝑉 → (𝑉 ∖ {𝑁}) ≈ 𝑃) |
22 | enfi 8718 | . . 3 ⊢ ((𝑉 ∖ {𝑁}) ≈ 𝑃 → ((𝑉 ∖ {𝑁}) ∈ Fin ↔ 𝑃 ∈ Fin)) | |
23 | 21, 22 | syl 17 | . 2 ⊢ (𝑁 ∈ 𝑉 → ((𝑉 ∖ {𝑁}) ∈ Fin ↔ 𝑃 ∈ Fin)) |
24 | 8, 23 | bitrd 282 | 1 ⊢ (𝑁 ∈ 𝑉 → (𝑉 ∈ Fin ↔ 𝑃 ∈ Fin)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 209 ∧ wa 399 = wceq 1538 ∃wex 1781 ∈ wcel 2111 ≠ wne 2987 ∃wrex 3107 {crab 3110 Vcvv 3441 ∖ cdif 3878 𝒫 cpw 4497 {csn 4525 {cpr 4527 class class class wbr 5030 ↦ cmpt 5110 –1-1-onto→wf1o 6323 ‘cfv 6324 ≈ cen 8489 Fincfn 8492 Vtxcvtx 26789 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2158 ax-12 2175 ax-ext 2770 ax-rep 5154 ax-sep 5167 ax-nul 5174 ax-pow 5231 ax-pr 5295 ax-un 7441 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3or 1085 df-3an 1086 df-tru 1541 df-ex 1782 df-nf 1786 df-sb 2070 df-mo 2598 df-eu 2629 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-ne 2988 df-ral 3111 df-rex 3112 df-reu 3113 df-rab 3115 df-v 3443 df-sbc 3721 df-csb 3829 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-pss 3900 df-nul 4244 df-if 4426 df-pw 4499 df-sn 4526 df-pr 4528 df-tp 4530 df-op 4532 df-uni 4801 df-int 4839 df-iun 4883 df-br 5031 df-opab 5093 df-mpt 5111 df-tr 5137 df-id 5425 df-eprel 5430 df-po 5438 df-so 5439 df-fr 5478 df-we 5480 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-rn 5530 df-res 5531 df-ima 5532 df-pred 6116 df-ord 6162 df-on 6163 df-lim 6164 df-suc 6165 df-iota 6283 df-fun 6326 df-fn 6327 df-f 6328 df-f1 6329 df-fo 6330 df-f1o 6331 df-fv 6332 df-ov 7138 df-oprab 7139 df-mpo 7140 df-om 7561 df-wrecs 7930 df-recs 7991 df-rdg 8029 df-1o 8085 df-oadd 8089 df-er 8272 df-en 8493 df-fin 8496 |
This theorem is referenced by: cusgrfi 27248 |
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