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Mathbox for Glauco Siliprandi |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > nnfoctb | Structured version Visualization version GIF version |
Description: There exists a mapping from ℕ onto any (nonempty) countable set. (Contributed by Glauco Siliprandi, 17-Aug-2020.) |
Ref | Expression |
---|---|
nnfoctb | ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → ∃𝑓 𝑓:ℕ–onto→𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr 484 | . . 3 ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → 𝐴 ≠ ∅) | |
2 | reldom 8947 | . . . . . . 7 ⊢ Rel ≼ | |
3 | 2 | a1i 11 | . . . . . 6 ⊢ (𝐴 ≼ ω → Rel ≼ ) |
4 | brrelex1 5722 | . . . . . 6 ⊢ ((Rel ≼ ∧ 𝐴 ≼ ω) → 𝐴 ∈ V) | |
5 | 3, 4 | mpancom 685 | . . . . 5 ⊢ (𝐴 ≼ ω → 𝐴 ∈ V) |
6 | 0sdomg 9106 | . . . . 5 ⊢ (𝐴 ∈ V → (∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅)) | |
7 | 5, 6 | syl 17 | . . . 4 ⊢ (𝐴 ≼ ω → (∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅)) |
8 | 7 | adantr 480 | . . 3 ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → (∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅)) |
9 | 1, 8 | mpbird 257 | . 2 ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → ∅ ≺ 𝐴) |
10 | nnenom 13951 | . . . . . 6 ⊢ ℕ ≈ ω | |
11 | 10 | ensymi 9002 | . . . . 5 ⊢ ω ≈ ℕ |
12 | 11 | a1i 11 | . . . 4 ⊢ (𝐴 ≼ ω → ω ≈ ℕ) |
13 | domentr 9011 | . . . 4 ⊢ ((𝐴 ≼ ω ∧ ω ≈ ℕ) → 𝐴 ≼ ℕ) | |
14 | 12, 13 | mpdan 684 | . . 3 ⊢ (𝐴 ≼ ω → 𝐴 ≼ ℕ) |
15 | 14 | adantr 480 | . 2 ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → 𝐴 ≼ ℕ) |
16 | fodomr 9130 | . 2 ⊢ ((∅ ≺ 𝐴 ∧ 𝐴 ≼ ℕ) → ∃𝑓 𝑓:ℕ–onto→𝐴) | |
17 | 9, 15, 16 | syl2anc 583 | 1 ⊢ ((𝐴 ≼ ω ∧ 𝐴 ≠ ∅) → ∃𝑓 𝑓:ℕ–onto→𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 ∃wex 1773 ∈ wcel 2098 ≠ wne 2934 Vcvv 3468 ∅c0 4317 class class class wbr 5141 Rel wrel 5674 –onto→wfo 6535 ωcom 7852 ≈ cen 8938 ≼ cdom 8939 ≺ csdm 8940 ℕcn 12216 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2163 ax-ext 2697 ax-sep 5292 ax-nul 5299 ax-pow 5356 ax-pr 5420 ax-un 7722 ax-inf2 9638 ax-cnex 11168 ax-resscn 11169 ax-1cn 11170 ax-icn 11171 ax-addcl 11172 ax-addrcl 11173 ax-mulcl 11174 ax-mulrcl 11175 ax-mulcom 11176 ax-addass 11177 ax-mulass 11178 ax-distr 11179 ax-i2m1 11180 ax-1ne0 11181 ax-1rid 11182 ax-rnegex 11183 ax-rrecex 11184 ax-cnre 11185 ax-pre-lttri 11186 ax-pre-lttrn 11187 ax-pre-ltadd 11188 ax-pre-mulgt0 11189 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2704 df-cleq 2718 df-clel 2804 df-nfc 2879 df-ne 2935 df-nel 3041 df-ral 3056 df-rex 3065 df-reu 3371 df-rab 3427 df-v 3470 df-sbc 3773 df-csb 3889 df-dif 3946 df-un 3948 df-in 3950 df-ss 3960 df-pss 3962 df-nul 4318 df-if 4524 df-pw 4599 df-sn 4624 df-pr 4626 df-op 4630 df-uni 4903 df-iun 4992 df-br 5142 df-opab 5204 df-mpt 5225 df-tr 5259 df-id 5567 df-eprel 5573 df-po 5581 df-so 5582 df-fr 5624 df-we 5626 df-xp 5675 df-rel 5676 df-cnv 5677 df-co 5678 df-dm 5679 df-rn 5680 df-res 5681 df-ima 5682 df-pred 6294 df-ord 6361 df-on 6362 df-lim 6363 df-suc 6364 df-iota 6489 df-fun 6539 df-fn 6540 df-f 6541 df-f1 6542 df-fo 6543 df-f1o 6544 df-fv 6545 df-riota 7361 df-ov 7408 df-oprab 7409 df-mpo 7410 df-om 7853 df-2nd 7975 df-frecs 8267 df-wrecs 8298 df-recs 8372 df-rdg 8411 df-er 8705 df-en 8942 df-dom 8943 df-sdom 8944 df-pnf 11254 df-mnf 11255 df-xr 11256 df-ltxr 11257 df-le 11258 df-sub 11450 df-neg 11451 df-nn 12217 df-n0 12477 df-z 12563 df-uz 12827 |
This theorem is referenced by: ssnnf1octb 44470 issalnnd 45638 nnfoctbdj 45749 |
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