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Theorem modval 12618
 Description: The value of the modulo operation. The modulo congruence notation of number theory, 𝐽≡𝐾 (modulo 𝑁), can be expressed in our notation as (𝐽 mod 𝑁) = (𝐾 mod 𝑁). Definition 1 in Knuth, The Art of Computer Programming, Vol. I (1972), p. 38. Knuth uses "mod" for the operation and "modulo" for the congruence. Unlike Knuth, we restrict the second argument to positive reals to simplify certain theorems. (This also gives us future flexibility to extend it to any one of several different conventions for a zero or negative second argument, should there be an advantage in doing so.) (Contributed by NM, 10-Nov-2008.) (Revised by Mario Carneiro, 3-Nov-2013.)
Assertion
Ref Expression
modval ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ+) → (𝐴 mod 𝐵) = (𝐴 − (𝐵 · (⌊‘(𝐴 / 𝐵)))))

Proof of Theorem modval
Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 oveq1 6617 . . . . 5 (𝑥 = 𝐴 → (𝑥 / 𝑦) = (𝐴 / 𝑦))
21fveq2d 6157 . . . 4 (𝑥 = 𝐴 → (⌊‘(𝑥 / 𝑦)) = (⌊‘(𝐴 / 𝑦)))
32oveq2d 6626 . . 3 (𝑥 = 𝐴 → (𝑦 · (⌊‘(𝑥 / 𝑦))) = (𝑦 · (⌊‘(𝐴 / 𝑦))))
4 oveq12 6619 . . 3 ((𝑥 = 𝐴 ∧ (𝑦 · (⌊‘(𝑥 / 𝑦))) = (𝑦 · (⌊‘(𝐴 / 𝑦)))) → (𝑥 − (𝑦 · (⌊‘(𝑥 / 𝑦)))) = (𝐴 − (𝑦 · (⌊‘(𝐴 / 𝑦)))))
53, 4mpdan 701 . 2 (𝑥 = 𝐴 → (𝑥 − (𝑦 · (⌊‘(𝑥 / 𝑦)))) = (𝐴 − (𝑦 · (⌊‘(𝐴 / 𝑦)))))
6 oveq2 6618 . . . . 5 (𝑦 = 𝐵 → (𝐴 / 𝑦) = (𝐴 / 𝐵))
76fveq2d 6157 . . . 4 (𝑦 = 𝐵 → (⌊‘(𝐴 / 𝑦)) = (⌊‘(𝐴 / 𝐵)))
8 oveq12 6619 . . . 4 ((𝑦 = 𝐵 ∧ (⌊‘(𝐴 / 𝑦)) = (⌊‘(𝐴 / 𝐵))) → (𝑦 · (⌊‘(𝐴 / 𝑦))) = (𝐵 · (⌊‘(𝐴 / 𝐵))))
97, 8mpdan 701 . . 3 (𝑦 = 𝐵 → (𝑦 · (⌊‘(𝐴 / 𝑦))) = (𝐵 · (⌊‘(𝐴 / 𝐵))))
109oveq2d 6626 . 2 (𝑦 = 𝐵 → (𝐴 − (𝑦 · (⌊‘(𝐴 / 𝑦)))) = (𝐴 − (𝐵 · (⌊‘(𝐴 / 𝐵)))))
11 df-mod 12617 . 2 mod = (𝑥 ∈ ℝ, 𝑦 ∈ ℝ+ ↦ (𝑥 − (𝑦 · (⌊‘(𝑥 / 𝑦)))))
12 ovex 6638 . 2 (𝐴 − (𝐵 · (⌊‘(𝐴 / 𝐵)))) ∈ V
135, 10, 11, 12ovmpt2 6756 1 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ+) → (𝐴 mod 𝐵) = (𝐴 − (𝐵 · (⌊‘(𝐴 / 𝐵)))))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ wa 384   = wceq 1480   ∈ wcel 1987  ‘cfv 5852  (class class class)co 6610  ℝcr 9887   · cmul 9893   − cmin 10218   / cdiv 10636  ℝ+crp 11784  ⌊cfl 12539   mod cmo 12616 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-9 1996  ax-10 2016  ax-11 2031  ax-12 2044  ax-13 2245  ax-ext 2601  ax-sep 4746  ax-nul 4754  ax-pr 4872 This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1038  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1878  df-eu 2473  df-mo 2474  df-clab 2608  df-cleq 2614  df-clel 2617  df-nfc 2750  df-ral 2912  df-rex 2913  df-rab 2916  df-v 3191  df-sbc 3422  df-dif 3562  df-un 3564  df-in 3566  df-ss 3573  df-nul 3897  df-if 4064  df-sn 4154  df-pr 4156  df-op 4160  df-uni 4408  df-br 4619  df-opab 4679  df-id 4994  df-xp 5085  df-rel 5086  df-cnv 5087  df-co 5088  df-dm 5089  df-iota 5815  df-fun 5854  df-fv 5860  df-ov 6613  df-oprab 6614  df-mpt2 6615  df-mod 12617 This theorem is referenced by:  modvalr  12619  modcl  12620  mod0  12623  modge0  12626  modlt  12627  moddiffl  12629  modfrac  12631  modmulnn  12636  zmodcl  12638  modid  12643  modcyc  12653  modadd1  12655  modmul1  12671  moddi  12686  modsubdir  12687  modirr  12689  iexpcyc  12917  digit2  12945  dvdsmod  14985  divalgmod  15064  divalgmodOLD  15065  modgcd  15188  bezoutlem3  15193  prmdiv  15425  odzdvds  15435  fldivp1  15536  mulgmodid  17513  odmodnn0  17891  odmod  17897  gexdvds  17931  zringlpirlem3  19766  sineq0  24194  efif1olem2  24210  lgseisenlem4  25020  dchrisumlem1  25095  ostth2lem2  25240  sineq0ALT  38691  ltmod  39302  fourierswlem  39780
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