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Theorem fallfacval 16042
Description: The value of the falling factorial function. (Contributed by Scott Fenton, 5-Jan-2018.)
Assertion
Ref Expression
fallfacval ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ (0...(𝑁 − 1))(𝐴𝑘))
Distinct variable groups:   𝐴,𝑘   𝑘,𝑁

Proof of Theorem fallfacval
Dummy variables 𝑛 𝑥 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 oveq1 7438 . . 3 (𝑥 = 𝐴 → (𝑥𝑘) = (𝐴𝑘))
21prodeq2sdv 15956 . 2 (𝑥 = 𝐴 → ∏𝑘 ∈ (0...(𝑛 − 1))(𝑥𝑘) = ∏𝑘 ∈ (0...(𝑛 − 1))(𝐴𝑘))
3 oveq1 7438 . . . 4 (𝑛 = 𝑁 → (𝑛 − 1) = (𝑁 − 1))
43oveq2d 7447 . . 3 (𝑛 = 𝑁 → (0...(𝑛 − 1)) = (0...(𝑁 − 1)))
54prodeq1d 15953 . 2 (𝑛 = 𝑁 → ∏𝑘 ∈ (0...(𝑛 − 1))(𝐴𝑘) = ∏𝑘 ∈ (0...(𝑁 − 1))(𝐴𝑘))
6 df-fallfac 16040 . 2 FallFac = (𝑥 ∈ ℂ, 𝑛 ∈ ℕ0 ↦ ∏𝑘 ∈ (0...(𝑛 − 1))(𝑥𝑘))
7 prodex 15938 . 2 𝑘 ∈ (0...(𝑁 − 1))(𝐴𝑘) ∈ V
82, 5, 6, 7ovmpo 7593 1 ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ (0...(𝑁 − 1))(𝐴𝑘))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 395   = wceq 1537  wcel 2106  (class class class)co 7431  cc 11151  0cc0 11153  1c1 11154  cmin 11490  0cn0 12524  ...cfz 13544  cprod 15936   FallFac cfallfac 16037
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pr 5438
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-rab 3434  df-v 3480  df-sbc 3792  df-csb 3909  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5583  df-xp 5695  df-rel 5696  df-cnv 5697  df-co 5698  df-dm 5699  df-rn 5700  df-res 5701  df-ima 5702  df-pred 6323  df-iota 6516  df-fun 6565  df-f 6567  df-f1 6568  df-fo 6569  df-f1o 6570  df-fv 6571  df-ov 7434  df-oprab 7435  df-mpo 7436  df-frecs 8305  df-wrecs 8336  df-recs 8410  df-rdg 8449  df-seq 14040  df-prod 15937  df-fallfac 16040
This theorem is referenced by:  fallfacval2  16044  fallfacval3  16045  fallfaccllem  16047  fallfacp1  16063  fallfacfwd  16069  0fallfac  16070  bcled  42160  bcle2d  42161  bcc0  44336
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