![]() |
Mathbox for ML |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > Mathboxes > iunctb2 | Structured version Visualization version GIF version |
Description: Using the axiom of countable choice ax-cc 10506, the countable union of countable sets is countable. See iunctb 10645 for a somewhat more general theorem. (Contributed by ML, 10-Dec-2020.) |
Ref | Expression |
---|---|
iunctb2 | ⊢ (∀𝑥 ∈ ω 𝐵 ≼ ω → ∪ 𝑥 ∈ ω 𝐵 ≼ ω) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | omex 9714 | . . 3 ⊢ ω ∈ V | |
2 | domrefg 9049 | . . 3 ⊢ (ω ∈ V → ω ≼ ω) | |
3 | 1, 2 | ax-mp 5 | . 2 ⊢ ω ≼ ω |
4 | iunctb 10645 | . 2 ⊢ ((ω ≼ ω ∧ ∀𝑥 ∈ ω 𝐵 ≼ ω) → ∪ 𝑥 ∈ ω 𝐵 ≼ ω) | |
5 | 3, 4 | mpan 689 | 1 ⊢ (∀𝑥 ∈ ω 𝐵 ≼ ω → ∪ 𝑥 ∈ ω 𝐵 ≼ ω) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∈ wcel 2108 ∀wral 3067 Vcvv 3488 ∪ ciun 5015 class class class wbr 5166 ωcom 7905 ≼ cdom 9003 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1793 ax-4 1807 ax-5 1909 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-10 2141 ax-11 2158 ax-12 2178 ax-ext 2711 ax-rep 5303 ax-sep 5317 ax-nul 5324 ax-pow 5383 ax-pr 5447 ax-un 7772 ax-inf2 9712 ax-cc 10506 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 847 df-3or 1088 df-3an 1089 df-tru 1540 df-fal 1550 df-ex 1778 df-nf 1782 df-sb 2065 df-mo 2543 df-eu 2572 df-clab 2718 df-cleq 2732 df-clel 2819 df-nfc 2895 df-ne 2947 df-ral 3068 df-rex 3077 df-rmo 3388 df-reu 3389 df-rab 3444 df-v 3490 df-sbc 3805 df-csb 3922 df-dif 3979 df-un 3981 df-in 3983 df-ss 3993 df-pss 3996 df-nul 4353 df-if 4549 df-pw 4624 df-sn 4649 df-pr 4651 df-op 4655 df-uni 4932 df-int 4971 df-iun 5017 df-br 5167 df-opab 5229 df-mpt 5250 df-tr 5284 df-id 5593 df-eprel 5599 df-po 5607 df-so 5608 df-fr 5652 df-se 5653 df-we 5654 df-xp 5706 df-rel 5707 df-cnv 5708 df-co 5709 df-dm 5710 df-rn 5711 df-res 5712 df-ima 5713 df-pred 6334 df-ord 6400 df-on 6401 df-lim 6402 df-suc 6403 df-iota 6527 df-fun 6577 df-fn 6578 df-f 6579 df-f1 6580 df-fo 6581 df-f1o 6582 df-fv 6583 df-isom 6584 df-riota 7406 df-ov 7453 df-oprab 7454 df-mpo 7455 df-om 7906 df-1st 8032 df-2nd 8033 df-frecs 8324 df-wrecs 8355 df-recs 8429 df-rdg 8468 df-1o 8524 df-er 8765 df-map 8888 df-en 9006 df-dom 9007 df-sdom 9008 df-fin 9009 df-oi 9581 df-card 10010 df-acn 10013 |
This theorem is referenced by: ctbssinf 37374 |
Copyright terms: Public domain | W3C validator |