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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 46802 | . 2 ⊢ digit = (𝑏 ∈ ℕ ↦ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏))) | |
2 | oveq1 7369 | . . . . 5 ⊢ (𝑏 = 𝐵 → (𝑏↑-𝑘) = (𝐵↑-𝑘)) | |
3 | 2 | fvoveq1d 7384 | . . . 4 ⊢ (𝑏 = 𝐵 → (⌊‘((𝑏↑-𝑘) · 𝑟)) = (⌊‘((𝐵↑-𝑘) · 𝑟))) |
4 | id 22 | . . . 4 ⊢ (𝑏 = 𝐵 → 𝑏 = 𝐵) | |
5 | 3, 4 | oveq12d 7380 | . . 3 ⊢ (𝑏 = 𝐵 → ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏) = ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) |
6 | 5 | mpoeq3dv 7441 | . 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 12517 | . . . 4 ⊢ ℤ ∈ V | |
9 | ovex 7395 | . . . 4 ⊢ (0[,)+∞) ∈ V | |
10 | 8, 9 | pm3.2i 471 | . . 3 ⊢ (ℤ ∈ V ∧ (0[,)+∞) ∈ V) |
11 | eqid 2731 | . . . 4 ⊢ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) | |
12 | 11 | mpoexg 8014 | . . 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 6976 | 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 3446 ‘cfv 6501 (class class class)co 7362 ∈ cmpo 7364 0cc0 11060 · cmul 11065 +∞cpnf 11195 -cneg 11395 ℕcn 12162 ℤcz 12508 [,)cico 13276 ⌊cfl 13705 mod cmo 13784 ↑cexp 13977 digitcdig 46801 |
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 2702 ax-rep 5247 ax-sep 5261 ax-nul 5268 ax-pow 5325 ax-pr 5389 ax-un 7677 ax-cnex 11116 ax-resscn 11117 |
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 2533 df-eu 2562 df-clab 2709 df-cleq 2723 df-clel 2809 df-nfc 2884 df-ne 2940 df-ral 3061 df-rex 3070 df-reu 3352 df-rab 3406 df-v 3448 df-sbc 3743 df-csb 3859 df-dif 3916 df-un 3918 df-in 3920 df-ss 3930 df-nul 4288 df-if 4492 df-pw 4567 df-sn 4592 df-pr 4594 df-op 4598 df-uni 4871 df-iun 4961 df-br 5111 df-opab 5173 df-mpt 5194 df-id 5536 df-xp 5644 df-rel 5645 df-cnv 5646 df-co 5647 df-dm 5648 df-rn 5649 df-res 5650 df-ima 5651 df-iota 6453 df-fun 6503 df-fn 6504 df-f 6505 df-f1 6506 df-fo 6507 df-f1o 6508 df-fv 6509 df-ov 7365 df-oprab 7366 df-mpo 7367 df-1st 7926 df-2nd 7927 df-neg 11397 df-z 12509 df-dig 46802 |
This theorem is referenced by: digval 46804 |
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