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Mirrors > Home > MPE Home > Th. List > infpssr | Structured version Visualization version GIF version |
Description: Dedekind infinity implies existence of a denumerable subset: take a single point witnessing the proper subset relation and iterate the embedding. (Contributed by Stefan O'Rear, 30-Oct-2014.) (Revised by Mario Carneiro, 16-May-2015.) |
Ref | Expression |
---|---|
infpssr | ⊢ ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ω ≼ 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pssnel 4306 | . . 3 ⊢ (𝑋 ⊊ 𝐴 → ∃𝑦(𝑦 ∈ 𝐴 ∧ ¬ 𝑦 ∈ 𝑋)) | |
2 | 1 | adantr 473 | . 2 ⊢ ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ∃𝑦(𝑦 ∈ 𝐴 ∧ ¬ 𝑦 ∈ 𝑋)) |
3 | eldif 3841 | . . . 4 ⊢ (𝑦 ∈ (𝐴 ∖ 𝑋) ↔ (𝑦 ∈ 𝐴 ∧ ¬ 𝑦 ∈ 𝑋)) | |
4 | pssss 3964 | . . . . . 6 ⊢ (𝑋 ⊊ 𝐴 → 𝑋 ⊆ 𝐴) | |
5 | bren 8321 | . . . . . . . 8 ⊢ (𝑋 ≈ 𝐴 ↔ ∃𝑓 𝑓:𝑋–1-1-onto→𝐴) | |
6 | simpr 477 | . . . . . . . . . . . . 13 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → 𝑓:𝑋–1-1-onto→𝐴) | |
7 | f1ofo 6456 | . . . . . . . . . . . . 13 ⊢ (𝑓:𝑋–1-1-onto→𝐴 → 𝑓:𝑋–onto→𝐴) | |
8 | forn 6427 | . . . . . . . . . . . . 13 ⊢ (𝑓:𝑋–onto→𝐴 → ran 𝑓 = 𝐴) | |
9 | 6, 7, 8 | 3syl 18 | . . . . . . . . . . . 12 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → ran 𝑓 = 𝐴) |
10 | vex 3420 | . . . . . . . . . . . . 13 ⊢ 𝑓 ∈ V | |
11 | 10 | rnex 7438 | . . . . . . . . . . . 12 ⊢ ran 𝑓 ∈ V |
12 | 9, 11 | syl6eqelr 2877 | . . . . . . . . . . 11 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → 𝐴 ∈ V) |
13 | simplr 757 | . . . . . . . . . . . 12 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → 𝑋 ⊆ 𝐴) | |
14 | simpll 755 | . . . . . . . . . . . 12 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → 𝑦 ∈ (𝐴 ∖ 𝑋)) | |
15 | eqid 2780 | . . . . . . . . . . . 12 ⊢ (rec(◡𝑓, 𝑦) ↾ ω) = (rec(◡𝑓, 𝑦) ↾ ω) | |
16 | 13, 6, 14, 15 | infpssrlem5 9533 | . . . . . . . . . . 11 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → (𝐴 ∈ V → ω ≼ 𝐴)) |
17 | 12, 16 | mpd 15 | . . . . . . . . . 10 ⊢ (((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) ∧ 𝑓:𝑋–1-1-onto→𝐴) → ω ≼ 𝐴) |
18 | 17 | ex 405 | . . . . . . . . 9 ⊢ ((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) → (𝑓:𝑋–1-1-onto→𝐴 → ω ≼ 𝐴)) |
19 | 18 | exlimdv 1893 | . . . . . . . 8 ⊢ ((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) → (∃𝑓 𝑓:𝑋–1-1-onto→𝐴 → ω ≼ 𝐴)) |
20 | 5, 19 | syl5bi 234 | . . . . . . 7 ⊢ ((𝑦 ∈ (𝐴 ∖ 𝑋) ∧ 𝑋 ⊆ 𝐴) → (𝑋 ≈ 𝐴 → ω ≼ 𝐴)) |
21 | 20 | ex 405 | . . . . . 6 ⊢ (𝑦 ∈ (𝐴 ∖ 𝑋) → (𝑋 ⊆ 𝐴 → (𝑋 ≈ 𝐴 → ω ≼ 𝐴))) |
22 | 4, 21 | syl5 34 | . . . . 5 ⊢ (𝑦 ∈ (𝐴 ∖ 𝑋) → (𝑋 ⊊ 𝐴 → (𝑋 ≈ 𝐴 → ω ≼ 𝐴))) |
23 | 22 | impd 402 | . . . 4 ⊢ (𝑦 ∈ (𝐴 ∖ 𝑋) → ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ω ≼ 𝐴)) |
24 | 3, 23 | sylbir 227 | . . 3 ⊢ ((𝑦 ∈ 𝐴 ∧ ¬ 𝑦 ∈ 𝑋) → ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ω ≼ 𝐴)) |
25 | 24 | exlimiv 1890 | . 2 ⊢ (∃𝑦(𝑦 ∈ 𝐴 ∧ ¬ 𝑦 ∈ 𝑋) → ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ω ≼ 𝐴)) |
26 | 2, 25 | mpcom 38 | 1 ⊢ ((𝑋 ⊊ 𝐴 ∧ 𝑋 ≈ 𝐴) → ω ≼ 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 387 = wceq 1508 ∃wex 1743 ∈ wcel 2051 Vcvv 3417 ∖ cdif 3828 ⊆ wss 3831 ⊊ wpss 3832 class class class wbr 4934 ◡ccnv 5410 ran crn 5412 ↾ cres 5413 –onto→wfo 6191 –1-1-onto→wf1o 6192 ωcom 7402 reccrdg 7855 ≈ cen 8309 ≼ cdom 8310 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1759 ax-4 1773 ax-5 1870 ax-6 1929 ax-7 1966 ax-8 2053 ax-9 2060 ax-10 2080 ax-11 2094 ax-12 2107 ax-13 2302 ax-ext 2752 ax-rep 5053 ax-sep 5064 ax-nul 5071 ax-pow 5123 ax-pr 5190 ax-un 7285 |
This theorem depends on definitions: df-bi 199 df-an 388 df-or 835 df-3or 1070 df-3an 1071 df-tru 1511 df-ex 1744 df-nf 1748 df-sb 2017 df-mo 2551 df-eu 2589 df-clab 2761 df-cleq 2773 df-clel 2848 df-nfc 2920 df-ne 2970 df-ral 3095 df-rex 3096 df-reu 3097 df-rab 3099 df-v 3419 df-sbc 3684 df-csb 3789 df-dif 3834 df-un 3836 df-in 3838 df-ss 3845 df-pss 3847 df-nul 4182 df-if 4354 df-pw 4427 df-sn 4445 df-pr 4447 df-tp 4449 df-op 4451 df-uni 4718 df-iun 4799 df-br 4935 df-opab 4997 df-mpt 5014 df-tr 5036 df-id 5316 df-eprel 5321 df-po 5330 df-so 5331 df-fr 5370 df-we 5372 df-xp 5417 df-rel 5418 df-cnv 5419 df-co 5420 df-dm 5421 df-rn 5422 df-res 5423 df-ima 5424 df-pred 5991 df-ord 6037 df-on 6038 df-lim 6039 df-suc 6040 df-iota 6157 df-fun 6195 df-fn 6196 df-f 6197 df-f1 6198 df-fo 6199 df-f1o 6200 df-fv 6201 df-om 7403 df-wrecs 7756 df-recs 7818 df-rdg 7856 df-en 8313 df-dom 8314 |
This theorem is referenced by: isfin4-2 9540 |
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