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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 7102), this provides a concrete example of a set which we cannot show to be finite or infinite, as seen another way at inffiexmid 7098. (Contributed by Jim Kingdon, 14-Feb-2026.) |
| Ref | Expression |
|---|---|
| pw1ninf | ⊢ ¬ ω ≼ 𝒫 1o |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pw1ndom3 16610 | . 2 ⊢ ¬ 3o ≼ 𝒫 1o | |
| 2 | 3onn 6690 | . . . 4 ⊢ 3o ∈ ω | |
| 3 | nnfi 7059 | . . . 4 ⊢ (3o ∈ ω → 3o ∈ Fin) | |
| 4 | fict 7055 | . . . 4 ⊢ (3o ∈ Fin → 3o ≼ ω) | |
| 5 | 2, 3, 4 | mp2b 8 | . . 3 ⊢ 3o ≼ ω |
| 6 | domtr 6959 | . . 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 2202 𝒫 cpw 3652 class class class wbr 4088 ωcom 4688 1oc1o 6575 3oc3o 6577 ≼ cdom 6908 Fincfn 6909 |
| 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 2204 ax-14 2205 ax-ext 2213 ax-sep 4207 ax-nul 4215 ax-pow 4264 ax-pr 4299 ax-un 4530 ax-setind 4635 ax-iinf 4686 |
| This theorem depends on definitions: df-bi 117 df-3an 1006 df-tru 1400 df-fal 1403 df-nf 1509 df-sb 1811 df-eu 2082 df-mo 2083 df-clab 2218 df-cleq 2224 df-clel 2227 df-nfc 2363 df-ne 2403 df-ral 2515 df-rex 2516 df-v 2804 df-sbc 3032 df-dif 3202 df-un 3204 df-in 3206 df-ss 3213 df-nul 3495 df-pw 3654 df-sn 3675 df-pr 3676 df-op 3678 df-uni 3894 df-int 3929 df-br 4089 df-opab 4151 df-tr 4188 df-id 4390 df-iord 4463 df-on 4465 df-suc 4468 df-iom 4689 df-xp 4731 df-rel 4732 df-cnv 4733 df-co 4734 df-dm 4735 df-rn 4736 df-res 4737 df-ima 4738 df-iota 5286 df-fun 5328 df-fn 5329 df-f 5330 df-f1 5331 df-fo 5332 df-f1o 5333 df-fv 5334 df-1o 6582 df-2o 6583 df-3o 6584 df-en 6910 df-dom 6911 df-fin 6912 |
| This theorem is referenced by: (None) |
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