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Mirrors > Home > MPE Home > Th. List > fallfacval3 | Structured version Visualization version GIF version |
Description: A product representation of falling factorial when 𝐴 is a nonnegative integer. (Contributed by Scott Fenton, 20-Mar-2018.) |
Ref | Expression |
---|---|
fallfacval3 | ⊢ (𝑁 ∈ (0...𝐴) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ ((𝐴 − (𝑁 − 1))...𝐴)𝑘) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elfz3nn0 13613 | . . . 4 ⊢ (𝑁 ∈ (0...𝐴) → 𝐴 ∈ ℕ0) | |
2 | 1 | nn0cnd 12550 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → 𝐴 ∈ ℂ) |
3 | elfznn0 13612 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → 𝑁 ∈ ℕ0) | |
4 | fallfacval 15971 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑗 ∈ (0...(𝑁 − 1))(𝐴 − 𝑗)) | |
5 | 2, 3, 4 | syl2anc 583 | . 2 ⊢ (𝑁 ∈ (0...𝐴) → (𝐴 FallFac 𝑁) = ∏𝑗 ∈ (0...(𝑁 − 1))(𝐴 − 𝑗)) |
6 | elfzel2 13517 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → 𝐴 ∈ ℤ) | |
7 | elfzel1 13518 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → 0 ∈ ℤ) | |
8 | elfzelz 13519 | . . . 4 ⊢ (𝑁 ∈ (0...𝐴) → 𝑁 ∈ ℤ) | |
9 | peano2zm 12621 | . . . 4 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
10 | 8, 9 | syl 17 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → (𝑁 − 1) ∈ ℤ) |
11 | elfzelz 13519 | . . . . 5 ⊢ (𝑗 ∈ (0...(𝑁 − 1)) → 𝑗 ∈ ℤ) | |
12 | 11 | zcnd 12683 | . . . 4 ⊢ (𝑗 ∈ (0...(𝑁 − 1)) → 𝑗 ∈ ℂ) |
13 | subcl 11475 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑗 ∈ ℂ) → (𝐴 − 𝑗) ∈ ℂ) | |
14 | 2, 12, 13 | syl2an 595 | . . 3 ⊢ ((𝑁 ∈ (0...𝐴) ∧ 𝑗 ∈ (0...(𝑁 − 1))) → (𝐴 − 𝑗) ∈ ℂ) |
15 | oveq2 7422 | . . 3 ⊢ (𝑗 = (𝐴 − 𝑘) → (𝐴 − 𝑗) = (𝐴 − (𝐴 − 𝑘))) | |
16 | 6, 7, 10, 14, 15 | fprodrev 15939 | . 2 ⊢ (𝑁 ∈ (0...𝐴) → ∏𝑗 ∈ (0...(𝑁 − 1))(𝐴 − 𝑗) = ∏𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0))(𝐴 − (𝐴 − 𝑘))) |
17 | 2 | subid1d 11576 | . . . 4 ⊢ (𝑁 ∈ (0...𝐴) → (𝐴 − 0) = 𝐴) |
18 | 17 | oveq2d 7430 | . . 3 ⊢ (𝑁 ∈ (0...𝐴) → ((𝐴 − (𝑁 − 1))...(𝐴 − 0)) = ((𝐴 − (𝑁 − 1))...𝐴)) |
19 | 2 | adantr 480 | . . . 4 ⊢ ((𝑁 ∈ (0...𝐴) ∧ 𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0))) → 𝐴 ∈ ℂ) |
20 | elfzelz 13519 | . . . . . 6 ⊢ (𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0)) → 𝑘 ∈ ℤ) | |
21 | 20 | zcnd 12683 | . . . . 5 ⊢ (𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0)) → 𝑘 ∈ ℂ) |
22 | 21 | adantl 481 | . . . 4 ⊢ ((𝑁 ∈ (0...𝐴) ∧ 𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0))) → 𝑘 ∈ ℂ) |
23 | 19, 22 | nncand 11592 | . . 3 ⊢ ((𝑁 ∈ (0...𝐴) ∧ 𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0))) → (𝐴 − (𝐴 − 𝑘)) = 𝑘) |
24 | 18, 23 | prodeq12dv 15888 | . 2 ⊢ (𝑁 ∈ (0...𝐴) → ∏𝑘 ∈ ((𝐴 − (𝑁 − 1))...(𝐴 − 0))(𝐴 − (𝐴 − 𝑘)) = ∏𝑘 ∈ ((𝐴 − (𝑁 − 1))...𝐴)𝑘) |
25 | 5, 16, 24 | 3eqtrd 2771 | 1 ⊢ (𝑁 ∈ (0...𝐴) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ ((𝐴 − (𝑁 − 1))...𝐴)𝑘) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1534 ∈ wcel 2099 (class class class)co 7414 ℂcc 11122 0cc0 11124 1c1 11125 − cmin 11460 ℕ0cn0 12488 ℤcz 12574 ...cfz 13502 ∏cprod 15867 FallFac cfallfac 15966 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2164 ax-ext 2698 ax-rep 5279 ax-sep 5293 ax-nul 5300 ax-pow 5359 ax-pr 5423 ax-un 7732 ax-inf2 9650 ax-cnex 11180 ax-resscn 11181 ax-1cn 11182 ax-icn 11183 ax-addcl 11184 ax-addrcl 11185 ax-mulcl 11186 ax-mulrcl 11187 ax-mulcom 11188 ax-addass 11189 ax-mulass 11190 ax-distr 11191 ax-i2m1 11192 ax-1ne0 11193 ax-1rid 11194 ax-rnegex 11195 ax-rrecex 11196 ax-cnre 11197 ax-pre-lttri 11198 ax-pre-lttrn 11199 ax-pre-ltadd 11200 ax-pre-mulgt0 11201 ax-pre-sup 11202 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2529 df-eu 2558 df-clab 2705 df-cleq 2719 df-clel 2805 df-nfc 2880 df-ne 2936 df-nel 3042 df-ral 3057 df-rex 3066 df-rmo 3371 df-reu 3372 df-rab 3428 df-v 3471 df-sbc 3775 df-csb 3890 df-dif 3947 df-un 3949 df-in 3951 df-ss 3961 df-pss 3963 df-nul 4319 df-if 4525 df-pw 4600 df-sn 4625 df-pr 4627 df-op 4631 df-uni 4904 df-int 4945 df-iun 4993 df-br 5143 df-opab 5205 df-mpt 5226 df-tr 5260 df-id 5570 df-eprel 5576 df-po 5584 df-so 5585 df-fr 5627 df-se 5628 df-we 5629 df-xp 5678 df-rel 5679 df-cnv 5680 df-co 5681 df-dm 5682 df-rn 5683 df-res 5684 df-ima 5685 df-pred 6299 df-ord 6366 df-on 6367 df-lim 6368 df-suc 6369 df-iota 6494 df-fun 6544 df-fn 6545 df-f 6546 df-f1 6547 df-fo 6548 df-f1o 6549 df-fv 6550 df-isom 6551 df-riota 7370 df-ov 7417 df-oprab 7418 df-mpo 7419 df-om 7863 df-1st 7985 df-2nd 7986 df-frecs 8278 df-wrecs 8309 df-recs 8383 df-rdg 8422 df-1o 8478 df-er 8716 df-en 8954 df-dom 8955 df-sdom 8956 df-fin 8957 df-sup 9451 df-oi 9519 df-card 9948 df-pnf 11266 df-mnf 11267 df-xr 11268 df-ltxr 11269 df-le 11270 df-sub 11462 df-neg 11463 df-div 11888 df-nn 12229 df-2 12291 df-3 12292 df-n0 12489 df-z 12575 df-uz 12839 df-rp 12993 df-fz 13503 df-fzo 13646 df-seq 13985 df-exp 14045 df-hash 14308 df-cj 15064 df-re 15065 df-im 15066 df-sqrt 15200 df-abs 15201 df-clim 15450 df-prod 15868 df-fallfac 15969 |
This theorem is referenced by: fallfacval4 16005 |
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