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| Mirrors > Home > ILE Home > Th. List > Mathboxes > pw1ninf | GIF version | ||
| Description: The powerset of 1o is not infinite. Since we cannot prove it is finite (see pw1fin 7211), this provides a concrete example of a set which we cannot show to be finite or infinite, as seen another way at inffiexmid 7207. (Contributed by Jim Kingdon, 14-Feb-2026.) |
| Ref | Expression |
|---|---|
| pw1ninf | ⊢ ¬ ω ≼ 𝒫 1o |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pw1ndom3 17003 | . 2 ⊢ ¬ 3o ≼ 𝒫 1o | |
| 2 | 3onn 6789 | . . . 4 ⊢ 3o ∈ ω | |
| 3 | nnfi 7168 | . . . 4 ⊢ (3o ∈ ω → 3o ∈ Fin) | |
| 4 | fict 7164 | . . . 4 ⊢ (3o ∈ Fin → 3o ≼ ω) | |
| 5 | 2, 3, 4 | mp2b 8 | . . 3 ⊢ 3o ≼ ω |
| 6 | domtr 7066 | . . 3 ⊢ ((3o ≼ ω ∧ ω ≼ 𝒫 1o) → 3o ≼ 𝒫 1o) | |
| 7 | 5, 6 | mpan 428 | . 2 ⊢ (ω ≼ 𝒫 1o → 3o ≼ 𝒫 1o) |
| 8 | 1, 7 | mto 672 | 1 ⊢ ¬ ω ≼ 𝒫 1o |
| Colors of variables: wff set class |
| Syntax hints: ¬ wn 3 ∈ wcel 2209 𝒫 cpw 3688 class class class wbr 4128 ωcom 4735 1oc1o 6674 3oc3o 6676 ≼ cdom 7015 Fincfn 7016 |
| 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-in1 623 ax-in2 624 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-sep 4247 ax-nul 4257 ax-pow 4309 ax-pr 4344 ax-un 4576 ax-setind 4682 ax-iinf 4733 |
| This theorem depends on definitions: df-bi 117 df-3an 1011 df-tru 1405 df-fal 1408 df-nf 1514 df-sb 1816 df-eu 2089 df-mo 2090 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ne 2421 df-ral 2533 df-rex 2534 df-v 2823 df-sbc 3052 df-dif 3222 df-un 3224 df-in 3226 df-ss 3233 df-nul 3521 df-pw 3690 df-sn 3714 df-pr 3715 df-op 3717 df-uni 3934 df-int 3969 df-br 4129 df-opab 4191 df-tr 4228 df-id 4436 df-iord 4509 df-on 4511 df-suc 4514 df-iom 4736 df-xp 4778 df-rel 4779 df-cnv 4780 df-co 4781 df-dm 4782 df-rn 4783 df-res 4784 df-ima 4785 df-iota 5335 df-fun 5377 df-fn 5378 df-f 5379 df-f1 5380 df-fo 5381 df-f1o 5382 df-fv 5383 df-1o 6681 df-2o 6682 df-3o 6683 df-en 7017 df-dom 7018 df-fin 7019 |
| This theorem is referenced by: (None) |
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