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Mathbox for Alexander van der Vekens |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > ackendofnn0 | Structured version Visualization version GIF version |
Description: The Ackermann function at any nonnegative integer is an endofunction on the nonnegative integers. (Contributed by AV, 8-May-2024.) |
Ref | Expression |
---|---|
ackendofnn0 | ⊢ (𝑀 ∈ ℕ0 → (Ack‘𝑀):ℕ0⟶ℕ0) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fveq2 6887 | . . 3 ⊢ (𝑥 = 0 → (Ack‘𝑥) = (Ack‘0)) | |
2 | 1 | feq1d 6698 | . 2 ⊢ (𝑥 = 0 → ((Ack‘𝑥):ℕ0⟶ℕ0 ↔ (Ack‘0):ℕ0⟶ℕ0)) |
3 | fveq2 6887 | . . 3 ⊢ (𝑥 = 𝑦 → (Ack‘𝑥) = (Ack‘𝑦)) | |
4 | 3 | feq1d 6698 | . 2 ⊢ (𝑥 = 𝑦 → ((Ack‘𝑥):ℕ0⟶ℕ0 ↔ (Ack‘𝑦):ℕ0⟶ℕ0)) |
5 | fveq2 6887 | . . 3 ⊢ (𝑥 = (𝑦 + 1) → (Ack‘𝑥) = (Ack‘(𝑦 + 1))) | |
6 | 5 | feq1d 6698 | . 2 ⊢ (𝑥 = (𝑦 + 1) → ((Ack‘𝑥):ℕ0⟶ℕ0 ↔ (Ack‘(𝑦 + 1)):ℕ0⟶ℕ0)) |
7 | fveq2 6887 | . . 3 ⊢ (𝑥 = 𝑀 → (Ack‘𝑥) = (Ack‘𝑀)) | |
8 | 7 | feq1d 6698 | . 2 ⊢ (𝑥 = 𝑀 → ((Ack‘𝑥):ℕ0⟶ℕ0 ↔ (Ack‘𝑀):ℕ0⟶ℕ0)) |
9 | ackval0 47267 | . . 3 ⊢ (Ack‘0) = (𝑛 ∈ ℕ0 ↦ (𝑛 + 1)) | |
10 | peano2nn0 12507 | . . 3 ⊢ (𝑛 ∈ ℕ0 → (𝑛 + 1) ∈ ℕ0) | |
11 | 9, 10 | fmpti 7106 | . 2 ⊢ (Ack‘0):ℕ0⟶ℕ0 |
12 | nn0ex 12473 | . . . . . . . 8 ⊢ ℕ0 ∈ V | |
13 | 12 | a1i 11 | . . . . . . 7 ⊢ (((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) ∧ 𝑛 ∈ ℕ0) → ℕ0 ∈ V) |
14 | simplr 768 | . . . . . . 7 ⊢ (((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) ∧ 𝑛 ∈ ℕ0) → (Ack‘𝑦):ℕ0⟶ℕ0) | |
15 | 10 | adantl 483 | . . . . . . 7 ⊢ (((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) ∧ 𝑛 ∈ ℕ0) → (𝑛 + 1) ∈ ℕ0) |
16 | 13, 14, 15 | itcovalendof 47256 | . . . . . 6 ⊢ (((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) ∧ 𝑛 ∈ ℕ0) → ((IterComp‘(Ack‘𝑦))‘(𝑛 + 1)):ℕ0⟶ℕ0) |
17 | 1nn0 12483 | . . . . . 6 ⊢ 1 ∈ ℕ0 | |
18 | ffvelcdm 7078 | . . . . . 6 ⊢ ((((IterComp‘(Ack‘𝑦))‘(𝑛 + 1)):ℕ0⟶ℕ0 ∧ 1 ∈ ℕ0) → (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1) ∈ ℕ0) | |
19 | 16, 17, 18 | sylancl 587 | . . . . 5 ⊢ (((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) ∧ 𝑛 ∈ ℕ0) → (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1) ∈ ℕ0) |
20 | eqid 2733 | . . . . 5 ⊢ (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1)) = (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1)) | |
21 | 19, 20 | fmptd 7108 | . . . 4 ⊢ ((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) → (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1)):ℕ0⟶ℕ0) |
22 | ackvalsuc1mpt 47265 | . . . . . 6 ⊢ (𝑦 ∈ ℕ0 → (Ack‘(𝑦 + 1)) = (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1))) | |
23 | 22 | adantr 482 | . . . . 5 ⊢ ((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) → (Ack‘(𝑦 + 1)) = (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1))) |
24 | 23 | feq1d 6698 | . . . 4 ⊢ ((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) → ((Ack‘(𝑦 + 1)):ℕ0⟶ℕ0 ↔ (𝑛 ∈ ℕ0 ↦ (((IterComp‘(Ack‘𝑦))‘(𝑛 + 1))‘1)):ℕ0⟶ℕ0)) |
25 | 21, 24 | mpbird 257 | . . 3 ⊢ ((𝑦 ∈ ℕ0 ∧ (Ack‘𝑦):ℕ0⟶ℕ0) → (Ack‘(𝑦 + 1)):ℕ0⟶ℕ0) |
26 | 25 | ex 414 | . 2 ⊢ (𝑦 ∈ ℕ0 → ((Ack‘𝑦):ℕ0⟶ℕ0 → (Ack‘(𝑦 + 1)):ℕ0⟶ℕ0)) |
27 | 2, 4, 6, 8, 11, 26 | nn0ind 12652 | 1 ⊢ (𝑀 ∈ ℕ0 → (Ack‘𝑀):ℕ0⟶ℕ0) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 397 = wceq 1542 ∈ wcel 2107 Vcvv 3475 ↦ cmpt 5229 ⟶wf 6535 ‘cfv 6539 (class class class)co 7403 0cc0 11105 1c1 11106 + caddc 11108 ℕ0cn0 12467 IterCompcitco 47244 Ackcack 47245 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-10 2138 ax-11 2155 ax-12 2172 ax-ext 2704 ax-rep 5283 ax-sep 5297 ax-nul 5304 ax-pow 5361 ax-pr 5425 ax-un 7719 ax-inf2 9631 ax-cnex 11161 ax-resscn 11162 ax-1cn 11163 ax-icn 11164 ax-addcl 11165 ax-addrcl 11166 ax-mulcl 11167 ax-mulrcl 11168 ax-mulcom 11169 ax-addass 11170 ax-mulass 11171 ax-distr 11172 ax-i2m1 11173 ax-1ne0 11174 ax-1rid 11175 ax-rnegex 11176 ax-rrecex 11177 ax-cnre 11178 ax-pre-lttri 11179 ax-pre-lttrn 11180 ax-pre-ltadd 11181 ax-pre-mulgt0 11182 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-nf 1787 df-sb 2069 df-mo 2535 df-eu 2564 df-clab 2711 df-cleq 2725 df-clel 2811 df-nfc 2886 df-ne 2942 df-nel 3048 df-ral 3063 df-rex 3072 df-reu 3378 df-rab 3434 df-v 3477 df-sbc 3776 df-csb 3892 df-dif 3949 df-un 3951 df-in 3953 df-ss 3963 df-pss 3965 df-nul 4321 df-if 4527 df-pw 4602 df-sn 4627 df-pr 4629 df-op 4633 df-uni 4907 df-iun 4997 df-br 5147 df-opab 5209 df-mpt 5230 df-tr 5264 df-id 5572 df-eprel 5578 df-po 5586 df-so 5587 df-fr 5629 df-we 5631 df-xp 5680 df-rel 5681 df-cnv 5682 df-co 5683 df-dm 5684 df-rn 5685 df-res 5686 df-ima 5687 df-pred 6296 df-ord 6363 df-on 6364 df-lim 6365 df-suc 6366 df-iota 6491 df-fun 6541 df-fn 6542 df-f 6543 df-f1 6544 df-fo 6545 df-f1o 6546 df-fv 6547 df-riota 7359 df-ov 7406 df-oprab 7407 df-mpo 7408 df-om 7850 df-2nd 7970 df-frecs 8260 df-wrecs 8291 df-recs 8365 df-rdg 8404 df-er 8698 df-en 8935 df-dom 8936 df-sdom 8937 df-pnf 11245 df-mnf 11246 df-xr 11247 df-ltxr 11248 df-le 11249 df-sub 11441 df-neg 11442 df-nn 12208 df-n0 12468 df-z 12554 df-uz 12818 df-seq 13962 df-itco 47246 df-ack 47247 |
This theorem is referenced by: ackfnnn0 47272 ackvalsucsucval 47275 |
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