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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 7172), this provides a concrete example of a set which we cannot show to be finite or infinite, as seen another way at inffiexmid 7168. (Contributed by Jim Kingdon, 14-Feb-2026.) |
| Ref | Expression |
|---|---|
| pw1ninf | ⊢ ¬ ω ≼ 𝒫 1o |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pw1ndom3 16813 | . 2 ⊢ ¬ 3o ≼ 𝒫 1o | |
| 2 | 3onn 6757 | . . . 4 ⊢ 3o ∈ ω | |
| 3 | nnfi 7129 | . . . 4 ⊢ (3o ∈ ω → 3o ∈ Fin) | |
| 4 | fict 7125 | . . . 4 ⊢ (3o ∈ Fin → 3o ≼ ω) | |
| 5 | 2, 3, 4 | mp2b 8 | . . 3 ⊢ 3o ≼ ω |
| 6 | domtr 7027 | . . 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 2205 𝒫 cpw 3671 class class class wbr 4111 ωcom 4714 1oc1o 6642 3oc3o 6644 ≼ cdom 6976 Fincfn 6977 |
| 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 717 ax-5 1496 ax-7 1497 ax-gen 1498 ax-ie1 1542 ax-ie2 1543 ax-8 1553 ax-10 1554 ax-11 1555 ax-i12 1556 ax-bndl 1558 ax-4 1559 ax-17 1575 ax-i9 1579 ax-ial 1583 ax-i5r 1584 ax-13 2207 ax-14 2208 ax-ext 2216 ax-sep 4230 ax-nul 4238 ax-pow 4289 ax-pr 4324 ax-un 4556 ax-setind 4661 ax-iinf 4712 |
| This theorem depends on definitions: df-bi 117 df-3an 1007 df-tru 1401 df-fal 1404 df-nf 1510 df-sb 1812 df-eu 2085 df-mo 2086 df-clab 2221 df-cleq 2227 df-clel 2230 df-nfc 2375 df-ne 2415 df-ral 2527 df-rex 2528 df-v 2817 df-sbc 3045 df-dif 3215 df-un 3217 df-in 3219 df-ss 3226 df-nul 3511 df-pw 3673 df-sn 3697 df-pr 3698 df-op 3700 df-uni 3917 df-int 3952 df-br 4112 df-opab 4174 df-tr 4211 df-id 4416 df-iord 4489 df-on 4491 df-suc 4494 df-iom 4715 df-xp 4757 df-rel 4758 df-cnv 4759 df-co 4760 df-dm 4761 df-rn 4762 df-res 4763 df-ima 4764 df-iota 5314 df-fun 5356 df-fn 5357 df-f 5358 df-f1 5359 df-fo 5360 df-f1o 5361 df-fv 5362 df-1o 6649 df-2o 6650 df-3o 6651 df-en 6978 df-dom 6979 df-fin 6980 |
| This theorem is referenced by: (None) |
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