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Mathbox for Alexander van der Vekens |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > digfval | Structured version Visualization version GIF version |
Description: Operation to obtain the 𝑘 th digit of a nonnegative real number 𝑟 in the positional system with base 𝐵. (Contributed by AV, 23-May-2020.) |
Ref | Expression |
---|---|
digfval | ⊢ (𝐵 ∈ ℕ → (digit‘𝐵) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-dig 46577 | . 2 ⊢ digit = (𝑏 ∈ ℕ ↦ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏))) | |
2 | oveq1 7358 | . . . . 5 ⊢ (𝑏 = 𝐵 → (𝑏↑-𝑘) = (𝐵↑-𝑘)) | |
3 | 2 | fvoveq1d 7373 | . . . 4 ⊢ (𝑏 = 𝐵 → (⌊‘((𝑏↑-𝑘) · 𝑟)) = (⌊‘((𝐵↑-𝑘) · 𝑟))) |
4 | id 22 | . . . 4 ⊢ (𝑏 = 𝐵 → 𝑏 = 𝐵) | |
5 | 3, 4 | oveq12d 7369 | . . 3 ⊢ (𝑏 = 𝐵 → ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏) = ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) |
6 | 5 | mpoeq3dv 7430 | . 2 ⊢ (𝑏 = 𝐵 → (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏)) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵))) |
7 | id 22 | . 2 ⊢ (𝐵 ∈ ℕ → 𝐵 ∈ ℕ) | |
8 | zex 12466 | . . . 4 ⊢ ℤ ∈ V | |
9 | ovex 7384 | . . . 4 ⊢ (0[,)+∞) ∈ V | |
10 | 8, 9 | pm3.2i 471 | . . 3 ⊢ (ℤ ∈ V ∧ (0[,)+∞) ∈ V) |
11 | eqid 2736 | . . . 4 ⊢ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) | |
12 | 11 | mpoexg 8001 | . . 3 ⊢ ((ℤ ∈ V ∧ (0[,)+∞) ∈ V) → (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) ∈ V) |
13 | 10, 12 | mp1i 13 | . 2 ⊢ (𝐵 ∈ ℕ → (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) ∈ V) |
14 | 1, 6, 7, 13 | fvmptd3 6968 | 1 ⊢ (𝐵 ∈ ℕ → (digit‘𝐵) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 396 = wceq 1541 ∈ wcel 2106 Vcvv 3443 ‘cfv 6493 (class class class)co 7351 ∈ cmpo 7353 0cc0 11009 · cmul 11014 +∞cpnf 11144 -cneg 11344 ℕcn 12111 ℤcz 12457 [,)cico 13220 ⌊cfl 13649 mod cmo 13728 ↑cexp 13921 digitcdig 46576 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2707 ax-rep 5240 ax-sep 5254 ax-nul 5261 ax-pow 5318 ax-pr 5382 ax-un 7664 ax-cnex 11065 ax-resscn 11066 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3or 1088 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2538 df-eu 2567 df-clab 2714 df-cleq 2728 df-clel 2814 df-nfc 2887 df-ne 2942 df-ral 3063 df-rex 3072 df-reu 3352 df-rab 3406 df-v 3445 df-sbc 3738 df-csb 3854 df-dif 3911 df-un 3913 df-in 3915 df-ss 3925 df-nul 4281 df-if 4485 df-pw 4560 df-sn 4585 df-pr 4587 df-op 4591 df-uni 4864 df-iun 4954 df-br 5104 df-opab 5166 df-mpt 5187 df-id 5529 df-xp 5637 df-rel 5638 df-cnv 5639 df-co 5640 df-dm 5641 df-rn 5642 df-res 5643 df-ima 5644 df-iota 6445 df-fun 6495 df-fn 6496 df-f 6497 df-f1 6498 df-fo 6499 df-f1o 6500 df-fv 6501 df-ov 7354 df-oprab 7355 df-mpo 7356 df-1st 7913 df-2nd 7914 df-neg 11346 df-z 12458 df-dig 46577 |
This theorem is referenced by: digval 46579 |
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