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Mirrors > Home > MPE Home > Th. List > winafp | Structured version Visualization version GIF version |
Description: A nontrivial weakly inaccessible cardinal is a fixed point of the aleph function. (Contributed by Mario Carneiro, 29-May-2014.) |
Ref | Expression |
---|---|
winafp | ⊢ ((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) → (ℵ‘𝐴) = 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | winalim2 9964 | . 2 ⊢ ((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) → ∃𝑥((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) | |
2 | vex 3440 | . . . . . . . . 9 ⊢ 𝑥 ∈ V | |
3 | limelon 6129 | . . . . . . . . 9 ⊢ ((𝑥 ∈ V ∧ Lim 𝑥) → 𝑥 ∈ On) | |
4 | 2, 3 | mpan 686 | . . . . . . . 8 ⊢ (Lim 𝑥 → 𝑥 ∈ On) |
5 | alephle 9360 | . . . . . . . 8 ⊢ (𝑥 ∈ On → 𝑥 ⊆ (ℵ‘𝑥)) | |
6 | 4, 5 | syl 17 | . . . . . . 7 ⊢ (Lim 𝑥 → 𝑥 ⊆ (ℵ‘𝑥)) |
7 | 6 | ad2antll 725 | . . . . . 6 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → 𝑥 ⊆ (ℵ‘𝑥)) |
8 | simprl 767 | . . . . . 6 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (ℵ‘𝑥) = 𝐴) | |
9 | 7, 8 | sseqtrd 3928 | . . . . 5 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → 𝑥 ⊆ 𝐴) |
10 | 8 | fveq2d 6542 | . . . . . . . 8 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (cf‘(ℵ‘𝑥)) = (cf‘𝐴)) |
11 | alephsing 9544 | . . . . . . . . 9 ⊢ (Lim 𝑥 → (cf‘(ℵ‘𝑥)) = (cf‘𝑥)) | |
12 | 11 | ad2antll 725 | . . . . . . . 8 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (cf‘(ℵ‘𝑥)) = (cf‘𝑥)) |
13 | 10, 12 | eqtr3d 2833 | . . . . . . 7 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (cf‘𝐴) = (cf‘𝑥)) |
14 | elwina 9954 | . . . . . . . . 9 ⊢ (𝐴 ∈ Inaccw ↔ (𝐴 ≠ ∅ ∧ (cf‘𝐴) = 𝐴 ∧ ∀𝑦 ∈ 𝐴 ∃𝑧 ∈ 𝐴 𝑦 ≺ 𝑧)) | |
15 | 14 | simp2bi 1139 | . . . . . . . 8 ⊢ (𝐴 ∈ Inaccw → (cf‘𝐴) = 𝐴) |
16 | 15 | ad2antrr 722 | . . . . . . 7 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (cf‘𝐴) = 𝐴) |
17 | 13, 16 | eqtr3d 2833 | . . . . . 6 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (cf‘𝑥) = 𝐴) |
18 | cfle 9522 | . . . . . 6 ⊢ (cf‘𝑥) ⊆ 𝑥 | |
19 | 17, 18 | syl6eqssr 3943 | . . . . 5 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → 𝐴 ⊆ 𝑥) |
20 | 9, 19 | eqssd 3906 | . . . 4 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → 𝑥 = 𝐴) |
21 | 20 | fveq2d 6542 | . . 3 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (ℵ‘𝑥) = (ℵ‘𝐴)) |
22 | 21, 8 | eqtr3d 2833 | . 2 ⊢ (((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) ∧ ((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) → (ℵ‘𝐴) = 𝐴) |
23 | 1, 22 | exlimddv 1913 | 1 ⊢ ((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) → (ℵ‘𝐴) = 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 396 = wceq 1522 ∈ wcel 2081 ≠ wne 2984 ∀wral 3105 ∃wrex 3106 Vcvv 3437 ⊆ wss 3859 ∅c0 4211 class class class wbr 4962 Oncon0 6066 Lim wlim 6067 ‘cfv 6225 ωcom 7436 ≺ csdm 8356 ℵcale 9211 cfccf 9212 Inaccwcwina 9950 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1777 ax-4 1791 ax-5 1888 ax-6 1947 ax-7 1992 ax-8 2083 ax-9 2091 ax-10 2112 ax-11 2126 ax-12 2141 ax-13 2344 ax-ext 2769 ax-rep 5081 ax-sep 5094 ax-nul 5101 ax-pow 5157 ax-pr 5221 ax-un 7319 ax-inf2 8950 |
This theorem depends on definitions: df-bi 208 df-an 397 df-or 843 df-3or 1081 df-3an 1082 df-tru 1525 df-ex 1762 df-nf 1766 df-sb 2043 df-mo 2576 df-eu 2612 df-clab 2776 df-cleq 2788 df-clel 2863 df-nfc 2935 df-ne 2985 df-ral 3110 df-rex 3111 df-reu 3112 df-rmo 3113 df-rab 3114 df-v 3439 df-sbc 3707 df-csb 3812 df-dif 3862 df-un 3864 df-in 3866 df-ss 3874 df-pss 3876 df-nul 4212 df-if 4382 df-pw 4455 df-sn 4473 df-pr 4475 df-tp 4477 df-op 4479 df-uni 4746 df-int 4783 df-iun 4827 df-br 4963 df-opab 5025 df-mpt 5042 df-tr 5064 df-id 5348 df-eprel 5353 df-po 5362 df-so 5363 df-fr 5402 df-se 5403 df-we 5404 df-xp 5449 df-rel 5450 df-cnv 5451 df-co 5452 df-dm 5453 df-rn 5454 df-res 5455 df-ima 5456 df-pred 6023 df-ord 6069 df-on 6070 df-lim 6071 df-suc 6072 df-iota 6189 df-fun 6227 df-fn 6228 df-f 6229 df-f1 6230 df-fo 6231 df-f1o 6232 df-fv 6233 df-isom 6234 df-riota 6977 df-ov 7019 df-oprab 7020 df-mpo 7021 df-om 7437 df-1st 7545 df-2nd 7546 df-wrecs 7798 df-smo 7835 df-recs 7860 df-rdg 7898 df-er 8139 df-map 8258 df-en 8358 df-dom 8359 df-sdom 8360 df-fin 8361 df-oi 8820 df-har 8868 df-card 9214 df-aleph 9215 df-cf 9216 df-acn 9217 df-wina 9952 |
This theorem is referenced by: winafpi 9966 |
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