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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 48248 | . 2 ⊢ digit = (𝑏 ∈ ℕ ↦ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏))) | |
2 | oveq1 7452 | . . . . 5 ⊢ (𝑏 = 𝐵 → (𝑏↑-𝑘) = (𝐵↑-𝑘)) | |
3 | 2 | fvoveq1d 7467 | . . . 4 ⊢ (𝑏 = 𝐵 → (⌊‘((𝑏↑-𝑘) · 𝑟)) = (⌊‘((𝐵↑-𝑘) · 𝑟))) |
4 | id 22 | . . . 4 ⊢ (𝑏 = 𝐵 → 𝑏 = 𝐵) | |
5 | 3, 4 | oveq12d 7463 | . . 3 ⊢ (𝑏 = 𝐵 → ((⌊‘((𝑏↑-𝑘) · 𝑟)) mod 𝑏) = ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) |
6 | 5 | mpoeq3dv 7525 | . 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 12644 | . . . 4 ⊢ ℤ ∈ V | |
9 | ovex 7478 | . . . 4 ⊢ (0[,)+∞) ∈ V | |
10 | 8, 9 | pm3.2i 470 | . . 3 ⊢ (ℤ ∈ V ∧ (0[,)+∞) ∈ V) |
11 | eqid 2734 | . . . 4 ⊢ (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) = (𝑘 ∈ ℤ, 𝑟 ∈ (0[,)+∞) ↦ ((⌊‘((𝐵↑-𝑘) · 𝑟)) mod 𝐵)) | |
12 | 11 | mpoexg 8113 | . . 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 7050 | 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 395 = wceq 1537 ∈ wcel 2103 Vcvv 3482 ‘cfv 6572 (class class class)co 7445 ∈ cmpo 7447 0cc0 11180 · cmul 11185 +∞cpnf 11317 -cneg 11517 ℕcn 12289 ℤcz 12635 [,)cico 13405 ⌊cfl 13837 mod cmo 13916 ↑cexp 14108 digitcdig 48247 |
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 2105 ax-9 2113 ax-10 2136 ax-11 2153 ax-12 2173 ax-ext 2705 ax-rep 5306 ax-sep 5320 ax-nul 5327 ax-pow 5386 ax-pr 5450 ax-un 7766 ax-cnex 11236 ax-resscn 11237 |
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 2537 df-eu 2566 df-clab 2712 df-cleq 2726 df-clel 2813 df-nfc 2890 df-ne 2943 df-ral 3064 df-rex 3073 df-reu 3384 df-rab 3439 df-v 3484 df-sbc 3799 df-csb 3916 df-dif 3973 df-un 3975 df-in 3977 df-ss 3987 df-nul 4348 df-if 4549 df-pw 4624 df-sn 4649 df-pr 4651 df-op 4655 df-uni 4932 df-iun 5021 df-br 5170 df-opab 5232 df-mpt 5253 df-id 5597 df-xp 5705 df-rel 5706 df-cnv 5707 df-co 5708 df-dm 5709 df-rn 5710 df-res 5711 df-ima 5712 df-iota 6524 df-fun 6574 df-fn 6575 df-f 6576 df-f1 6577 df-fo 6578 df-f1o 6579 df-fv 6580 df-ov 7448 df-oprab 7449 df-mpo 7450 df-1st 8026 df-2nd 8027 df-neg 11519 df-z 12636 df-dig 48248 |
This theorem is referenced by: digval 48250 |
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