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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 7107), this provides a concrete example of a set which we cannot show to be finite or infinite, as seen another way at inffiexmid 7103. (Contributed by Jim Kingdon, 14-Feb-2026.) |
| Ref | Expression |
|---|---|
| pw1ninf | ⊢ ¬ ω ≼ 𝒫 1o |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pw1ndom3 16649 | . 2 ⊢ ¬ 3o ≼ 𝒫 1o | |
| 2 | 3onn 6695 | . . . 4 ⊢ 3o ∈ ω | |
| 3 | nnfi 7064 | . . . 4 ⊢ (3o ∈ ω → 3o ∈ Fin) | |
| 4 | fict 7060 | . . . 4 ⊢ (3o ∈ Fin → 3o ≼ ω) | |
| 5 | 2, 3, 4 | mp2b 8 | . . 3 ⊢ 3o ≼ ω |
| 6 | domtr 6964 | . . 3 ⊢ ((3o ≼ ω ∧ ω ≼ 𝒫 1o) → 3o ≼ 𝒫 1o) | |
| 7 | 5, 6 | mpan 424 | . 2 ⊢ (ω ≼ 𝒫 1o → 3o ≼ 𝒫 1o) |
| 8 | 1, 7 | mto 668 | 1 ⊢ ¬ ω ≼ 𝒫 1o |
| Colors of variables: wff set class |
| Syntax hints: ¬ wn 3 ∈ wcel 2201 𝒫 cpw 3653 class class class wbr 4089 ωcom 4690 1oc1o 6580 3oc3o 6582 ≼ cdom 6913 Fincfn 6914 |
| 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 619 ax-in2 620 ax-io 716 ax-5 1495 ax-7 1496 ax-gen 1497 ax-ie1 1541 ax-ie2 1542 ax-8 1552 ax-10 1553 ax-11 1554 ax-i12 1555 ax-bndl 1557 ax-4 1558 ax-17 1574 ax-i9 1578 ax-ial 1582 ax-i5r 1583 ax-13 2203 ax-14 2204 ax-ext 2212 ax-sep 4208 ax-nul 4216 ax-pow 4266 ax-pr 4301 ax-un 4532 ax-setind 4637 ax-iinf 4688 |
| This theorem depends on definitions: df-bi 117 df-3an 1006 df-tru 1400 df-fal 1403 df-nf 1509 df-sb 1810 df-eu 2081 df-mo 2082 df-clab 2217 df-cleq 2223 df-clel 2226 df-nfc 2362 df-ne 2402 df-ral 2514 df-rex 2515 df-v 2803 df-sbc 3031 df-dif 3201 df-un 3203 df-in 3205 df-ss 3212 df-nul 3494 df-pw 3655 df-sn 3676 df-pr 3677 df-op 3679 df-uni 3895 df-int 3930 df-br 4090 df-opab 4152 df-tr 4189 df-id 4392 df-iord 4465 df-on 4467 df-suc 4470 df-iom 4691 df-xp 4733 df-rel 4734 df-cnv 4735 df-co 4736 df-dm 4737 df-rn 4738 df-res 4739 df-ima 4740 df-iota 5288 df-fun 5330 df-fn 5331 df-f 5332 df-f1 5333 df-fo 5334 df-f1o 5335 df-fv 5336 df-1o 6587 df-2o 6588 df-3o 6589 df-en 6915 df-dom 6916 df-fin 6917 |
| This theorem is referenced by: (None) |
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