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Mirrors > Home > MPE Home > Th. List > fprodfac | Structured version Visualization version GIF version |
Description: Factorial using product notation. (Contributed by Scott Fenton, 15-Dec-2017.) |
Ref | Expression |
---|---|
fprodfac | ⊢ (𝐴 ∈ ℕ0 → (!‘𝐴) = ∏𝑘 ∈ (1...𝐴)𝑘) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elnn0 11887 | . 2 ⊢ (𝐴 ∈ ℕ0 ↔ (𝐴 ∈ ℕ ∨ 𝐴 = 0)) | |
2 | facnn 13631 | . . . 4 ⊢ (𝐴 ∈ ℕ → (!‘𝐴) = (seq1( · , I )‘𝐴)) | |
3 | vex 3444 | . . . . . 6 ⊢ 𝑘 ∈ V | |
4 | fvi 6715 | . . . . . 6 ⊢ (𝑘 ∈ V → ( I ‘𝑘) = 𝑘) | |
5 | 3, 4 | mp1i 13 | . . . . 5 ⊢ ((𝐴 ∈ ℕ ∧ 𝑘 ∈ (1...𝐴)) → ( I ‘𝑘) = 𝑘) |
6 | elnnuz 12270 | . . . . . 6 ⊢ (𝐴 ∈ ℕ ↔ 𝐴 ∈ (ℤ≥‘1)) | |
7 | 6 | biimpi 219 | . . . . 5 ⊢ (𝐴 ∈ ℕ → 𝐴 ∈ (ℤ≥‘1)) |
8 | elfznn 12931 | . . . . . . 7 ⊢ (𝑘 ∈ (1...𝐴) → 𝑘 ∈ ℕ) | |
9 | 8 | nncnd 11641 | . . . . . 6 ⊢ (𝑘 ∈ (1...𝐴) → 𝑘 ∈ ℂ) |
10 | 9 | adantl 485 | . . . . 5 ⊢ ((𝐴 ∈ ℕ ∧ 𝑘 ∈ (1...𝐴)) → 𝑘 ∈ ℂ) |
11 | 5, 7, 10 | fprodser 15295 | . . . 4 ⊢ (𝐴 ∈ ℕ → ∏𝑘 ∈ (1...𝐴)𝑘 = (seq1( · , I )‘𝐴)) |
12 | 2, 11 | eqtr4d 2836 | . . 3 ⊢ (𝐴 ∈ ℕ → (!‘𝐴) = ∏𝑘 ∈ (1...𝐴)𝑘) |
13 | prod0 15289 | . . . . 5 ⊢ ∏𝑘 ∈ ∅ 𝑘 = 1 | |
14 | 13 | eqcomi 2807 | . . . 4 ⊢ 1 = ∏𝑘 ∈ ∅ 𝑘 |
15 | fveq2 6645 | . . . . 5 ⊢ (𝐴 = 0 → (!‘𝐴) = (!‘0)) | |
16 | fac0 13632 | . . . . 5 ⊢ (!‘0) = 1 | |
17 | 15, 16 | eqtrdi 2849 | . . . 4 ⊢ (𝐴 = 0 → (!‘𝐴) = 1) |
18 | oveq2 7143 | . . . . . 6 ⊢ (𝐴 = 0 → (1...𝐴) = (1...0)) | |
19 | fz10 12923 | . . . . . 6 ⊢ (1...0) = ∅ | |
20 | 18, 19 | eqtrdi 2849 | . . . . 5 ⊢ (𝐴 = 0 → (1...𝐴) = ∅) |
21 | 20 | prodeq1d 15267 | . . . 4 ⊢ (𝐴 = 0 → ∏𝑘 ∈ (1...𝐴)𝑘 = ∏𝑘 ∈ ∅ 𝑘) |
22 | 14, 17, 21 | 3eqtr4a 2859 | . . 3 ⊢ (𝐴 = 0 → (!‘𝐴) = ∏𝑘 ∈ (1...𝐴)𝑘) |
23 | 12, 22 | jaoi 854 | . 2 ⊢ ((𝐴 ∈ ℕ ∨ 𝐴 = 0) → (!‘𝐴) = ∏𝑘 ∈ (1...𝐴)𝑘) |
24 | 1, 23 | sylbi 220 | 1 ⊢ (𝐴 ∈ ℕ0 → (!‘𝐴) = ∏𝑘 ∈ (1...𝐴)𝑘) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 399 ∨ wo 844 = wceq 1538 ∈ wcel 2111 Vcvv 3441 ∅c0 4243 I cid 5424 ‘cfv 6324 (class class class)co 7135 ℂcc 10524 0cc0 10526 1c1 10527 · cmul 10531 ℕcn 11625 ℕ0cn0 11885 ℤ≥cuz 12231 ...cfz 12885 seqcseq 13364 !cfa 13629 ∏cprod 15251 |
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 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2158 ax-12 2175 ax-ext 2770 ax-rep 5154 ax-sep 5167 ax-nul 5174 ax-pow 5231 ax-pr 5295 ax-un 7441 ax-inf2 9088 ax-cnex 10582 ax-resscn 10583 ax-1cn 10584 ax-icn 10585 ax-addcl 10586 ax-addrcl 10587 ax-mulcl 10588 ax-mulrcl 10589 ax-mulcom 10590 ax-addass 10591 ax-mulass 10592 ax-distr 10593 ax-i2m1 10594 ax-1ne0 10595 ax-1rid 10596 ax-rnegex 10597 ax-rrecex 10598 ax-cnre 10599 ax-pre-lttri 10600 ax-pre-lttrn 10601 ax-pre-ltadd 10602 ax-pre-mulgt0 10603 ax-pre-sup 10604 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3or 1085 df-3an 1086 df-tru 1541 df-fal 1551 df-ex 1782 df-nf 1786 df-sb 2070 df-mo 2598 df-eu 2629 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-ne 2988 df-nel 3092 df-ral 3111 df-rex 3112 df-reu 3113 df-rmo 3114 df-rab 3115 df-v 3443 df-sbc 3721 df-csb 3829 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-pss 3900 df-nul 4244 df-if 4426 df-pw 4499 df-sn 4526 df-pr 4528 df-tp 4530 df-op 4532 df-uni 4801 df-int 4839 df-iun 4883 df-br 5031 df-opab 5093 df-mpt 5111 df-tr 5137 df-id 5425 df-eprel 5430 df-po 5438 df-so 5439 df-fr 5478 df-se 5479 df-we 5480 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-rn 5530 df-res 5531 df-ima 5532 df-pred 6116 df-ord 6162 df-on 6163 df-lim 6164 df-suc 6165 df-iota 6283 df-fun 6326 df-fn 6327 df-f 6328 df-f1 6329 df-fo 6330 df-f1o 6331 df-fv 6332 df-isom 6333 df-riota 7093 df-ov 7138 df-oprab 7139 df-mpo 7140 df-om 7561 df-1st 7671 df-2nd 7672 df-wrecs 7930 df-recs 7991 df-rdg 8029 df-1o 8085 df-oadd 8089 df-er 8272 df-en 8493 df-dom 8494 df-sdom 8495 df-fin 8496 df-sup 8890 df-oi 8958 df-card 9352 df-pnf 10666 df-mnf 10667 df-xr 10668 df-ltxr 10669 df-le 10670 df-sub 10861 df-neg 10862 df-div 11287 df-nn 11626 df-2 11688 df-3 11689 df-n0 11886 df-z 11970 df-uz 12232 df-rp 12378 df-fz 12886 df-fzo 13029 df-seq 13365 df-exp 13426 df-fac 13630 df-hash 13687 df-cj 14450 df-re 14451 df-im 14452 df-sqrt 14586 df-abs 14587 df-clim 14837 df-prod 15252 |
This theorem is referenced by: risefacfac 15381 fallfacval4 15389 prmolefac 16372 gausslemma2dlem1 25950 gausslemma2dlem6 25956 bcprod 33083 etransclem41 42917 |
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