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Theorem bcval5 10727
Description: Write out the top and bottom parts of the binomial coefficient (𝑁C𝐾) = (𝑁 · (𝑁 − 1) · ... · ((𝑁𝐾) + 1)) / 𝐾! explicitly. In this form, it is valid even for 𝑁 < 𝐾, although it is no longer valid for nonpositive 𝐾. (Contributed by Mario Carneiro, 22-May-2014.) (Revised by Jim Kingdon, 23-Apr-2023.)
Assertion
Ref Expression
bcval5 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → (𝑁C𝐾) = ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)))

Proof of Theorem bcval5
Dummy variables 𝑥 𝑘 𝑦 𝑓 𝑔 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 bcval2 10714 . . . 4 (𝐾 ∈ (0...𝑁) → (𝑁C𝐾) = ((!‘𝑁) / ((!‘(𝑁𝐾)) · (!‘𝐾))))
21adantl 277 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = ((!‘𝑁) / ((!‘(𝑁𝐾)) · (!‘𝐾))))
3 simprl 529 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ)) → 𝑘 ∈ ℂ)
4 simprr 531 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ)) → 𝑥 ∈ ℂ)
53, 4mulcld 7968 . . . . . . . 8 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ)) → (𝑘 · 𝑥) ∈ ℂ)
6 simpr1 1003 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ)) → 𝑘 ∈ ℂ)
7 simpr2 1004 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ)) → 𝑥 ∈ ℂ)
8 simpr3 1005 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ)) → 𝑦 ∈ ℂ)
96, 7, 8mulassd 7971 . . . . . . . 8 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ)) → ((𝑘 · 𝑥) · 𝑦) = (𝑘 · (𝑥 · 𝑦)))
10 simpll 527 . . . . . . . . . . . . 13 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℕ0)
1110nn0zd 9362 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℤ)
12 simplr 528 . . . . . . . . . . . . 13 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℕ)
1312nnzd 9363 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℤ)
1411, 13zsubcld 9369 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) ∈ ℤ)
1514peano2zd 9367 . . . . . . . . . 10 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) + 1) ∈ ℤ)
16 1red 7963 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 1 ∈ ℝ)
1712nnred 8921 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℝ)
1810nn0red 9219 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℝ)
1912nnge1d 8951 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 1 ≤ 𝐾)
2016, 17, 18, 19lesub2dd 8509 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) ≤ (𝑁 − 1))
2114zred 9364 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) ∈ ℝ)
22 leaddsub 8385 . . . . . . . . . . . 12 (((𝑁𝐾) ∈ ℝ ∧ 1 ∈ ℝ ∧ 𝑁 ∈ ℝ) → (((𝑁𝐾) + 1) ≤ 𝑁 ↔ (𝑁𝐾) ≤ (𝑁 − 1)))
2321, 16, 18, 22syl3anc 1238 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (((𝑁𝐾) + 1) ≤ 𝑁 ↔ (𝑁𝐾) ≤ (𝑁 − 1)))
2420, 23mpbird 167 . . . . . . . . . 10 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) + 1) ≤ 𝑁)
25 eluz2 9523 . . . . . . . . . 10 (𝑁 ∈ (ℤ‘((𝑁𝐾) + 1)) ↔ (((𝑁𝐾) + 1) ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ ((𝑁𝐾) + 1) ≤ 𝑁))
2615, 11, 24, 25syl3anbrc 1181 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ (ℤ‘((𝑁𝐾) + 1)))
2726adantrr 479 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → 𝑁 ∈ (ℤ‘((𝑁𝐾) + 1)))
28 simprr 531 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (𝑁𝐾) ∈ ℕ)
29 nnuz 9552 . . . . . . . . 9 ℕ = (ℤ‘1)
3028, 29eleqtrdi 2270 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (𝑁𝐾) ∈ (ℤ‘1))
31 fvi 5569 . . . . . . . . . 10 (𝑘 ∈ V → ( I ‘𝑘) = 𝑘)
3231elv 2741 . . . . . . . . 9 ( I ‘𝑘) = 𝑘
33 eluzelcn 9528 . . . . . . . . . 10 (𝑘 ∈ (ℤ‘1) → 𝑘 ∈ ℂ)
3433adantl 277 . . . . . . . . 9 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ 𝑘 ∈ (ℤ‘1)) → 𝑘 ∈ ℂ)
3532, 34eqeltrid 2264 . . . . . . . 8 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) ∧ 𝑘 ∈ (ℤ‘1)) → ( I ‘𝑘) ∈ ℂ)
365, 9, 27, 30, 35seq3split 10465 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (seq1( · , I )‘𝑁) = ((seq1( · , I )‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)))
37 elfzuz3 10008 . . . . . . . . . . 11 (𝐾 ∈ (0...𝑁) → 𝑁 ∈ (ℤ𝐾))
3837adantl 277 . . . . . . . . . 10 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ (ℤ𝐾))
39 eluznn 9589 . . . . . . . . . 10 ((𝐾 ∈ ℕ ∧ 𝑁 ∈ (ℤ𝐾)) → 𝑁 ∈ ℕ)
4012, 38, 39syl2anc 411 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℕ)
4140adantrr 479 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → 𝑁 ∈ ℕ)
42 facnn 10691 . . . . . . . 8 (𝑁 ∈ ℕ → (!‘𝑁) = (seq1( · , I )‘𝑁))
4341, 42syl 14 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (!‘𝑁) = (seq1( · , I )‘𝑁))
44 facnn 10691 . . . . . . . . 9 ((𝑁𝐾) ∈ ℕ → (!‘(𝑁𝐾)) = (seq1( · , I )‘(𝑁𝐾)))
4528, 44syl 14 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (!‘(𝑁𝐾)) = (seq1( · , I )‘(𝑁𝐾)))
4645oveq1d 5884 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)) = ((seq1( · , I )‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)))
4736, 43, 463eqtr4d 2220 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ (𝐾 ∈ (0...𝑁) ∧ (𝑁𝐾) ∈ ℕ)) → (!‘𝑁) = ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)))
4847expr 375 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) ∈ ℕ → (!‘𝑁) = ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁))))
4910faccld 10700 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝑁) ∈ ℕ)
5049nncnd 8922 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝑁) ∈ ℂ)
5150mulid2d 7966 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (1 · (!‘𝑁)) = (!‘𝑁))
5240, 42syl 14 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝑁) = (seq1( · , I )‘𝑁))
5352oveq2d 5885 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (1 · (!‘𝑁)) = (1 · (seq1( · , I )‘𝑁)))
5451, 53eqtr3d 2212 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝑁) = (1 · (seq1( · , I )‘𝑁)))
55 fveq2 5511 . . . . . . . . 9 ((𝑁𝐾) = 0 → (!‘(𝑁𝐾)) = (!‘0))
56 fac0 10692 . . . . . . . . 9 (!‘0) = 1
5755, 56eqtrdi 2226 . . . . . . . 8 ((𝑁𝐾) = 0 → (!‘(𝑁𝐾)) = 1)
58 oveq1 5876 . . . . . . . . . . 11 ((𝑁𝐾) = 0 → ((𝑁𝐾) + 1) = (0 + 1))
59 0p1e1 9022 . . . . . . . . . . 11 (0 + 1) = 1
6058, 59eqtrdi 2226 . . . . . . . . . 10 ((𝑁𝐾) = 0 → ((𝑁𝐾) + 1) = 1)
6160seqeq1d 10437 . . . . . . . . 9 ((𝑁𝐾) = 0 → seq((𝑁𝐾) + 1)( · , I ) = seq1( · , I ))
6261fveq1d 5513 . . . . . . . 8 ((𝑁𝐾) = 0 → (seq((𝑁𝐾) + 1)( · , I )‘𝑁) = (seq1( · , I )‘𝑁))
6357, 62oveq12d 5887 . . . . . . 7 ((𝑁𝐾) = 0 → ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)) = (1 · (seq1( · , I )‘𝑁)))
6463eqeq2d 2189 . . . . . 6 ((𝑁𝐾) = 0 → ((!‘𝑁) = ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)) ↔ (!‘𝑁) = (1 · (seq1( · , I )‘𝑁))))
6554, 64syl5ibrcom 157 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) = 0 → (!‘𝑁) = ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁))))
66 fznn0sub 10043 . . . . . . 7 (𝐾 ∈ (0...𝑁) → (𝑁𝐾) ∈ ℕ0)
6766adantl 277 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) ∈ ℕ0)
68 elnn0 9167 . . . . . 6 ((𝑁𝐾) ∈ ℕ0 ↔ ((𝑁𝐾) ∈ ℕ ∨ (𝑁𝐾) = 0))
6967, 68sylib 122 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) ∈ ℕ ∨ (𝑁𝐾) = 0))
7048, 65, 69mpjaod 718 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝑁) = ((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)))
7170oveq1d 5884 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → ((!‘𝑁) / ((!‘(𝑁𝐾)) · (!‘𝐾))) = (((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)) / ((!‘(𝑁𝐾)) · (!‘𝐾))))
72 eqid 2177 . . . . . 6 (ℤ‘((𝑁𝐾) + 1)) = (ℤ‘((𝑁𝐾) + 1))
73 fvi 5569 . . . . . . . 8 (𝑓 ∈ V → ( I ‘𝑓) = 𝑓)
7473elv 2741 . . . . . . 7 ( I ‘𝑓) = 𝑓
75 eluzelcn 9528 . . . . . . . 8 (𝑓 ∈ (ℤ‘((𝑁𝐾) + 1)) → 𝑓 ∈ ℂ)
7675adantl 277 . . . . . . 7 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) ∧ 𝑓 ∈ (ℤ‘((𝑁𝐾) + 1))) → 𝑓 ∈ ℂ)
7774, 76eqeltrid 2264 . . . . . 6 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) ∧ 𝑓 ∈ (ℤ‘((𝑁𝐾) + 1))) → ( I ‘𝑓) ∈ ℂ)
78 mulcl 7929 . . . . . . 7 ((𝑓 ∈ ℂ ∧ 𝑔 ∈ ℂ) → (𝑓 · 𝑔) ∈ ℂ)
7978adantl 277 . . . . . 6 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) ∧ (𝑓 ∈ ℂ ∧ 𝑔 ∈ ℂ)) → (𝑓 · 𝑔) ∈ ℂ)
8072, 15, 77, 79seqf 10447 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → seq((𝑁𝐾) + 1)( · , I ):(ℤ‘((𝑁𝐾) + 1))⟶ℂ)
8180, 26ffvelcdmd 5648 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (seq((𝑁𝐾) + 1)( · , I )‘𝑁) ∈ ℂ)
8212nnnn0d 9218 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℕ0)
8382faccld 10700 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) ∈ ℕ)
8483nncnd 8922 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) ∈ ℂ)
8567faccld 10700 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘(𝑁𝐾)) ∈ ℕ)
8685nncnd 8922 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘(𝑁𝐾)) ∈ ℂ)
8783nnap0d 8954 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) # 0)
8885nnap0d 8954 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (!‘(𝑁𝐾)) # 0)
8981, 84, 86, 87, 88divcanap5d 8763 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (((!‘(𝑁𝐾)) · (seq((𝑁𝐾) + 1)( · , I )‘𝑁)) / ((!‘(𝑁𝐾)) · (!‘𝐾))) = ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)))
902, 71, 893eqtrd 2214 . 2 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)))
91 simplr 528 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℕ)
9291nnnn0d 9218 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℕ0)
9392faccld 10700 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) ∈ ℕ)
9493nncnd 8922 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) ∈ ℂ)
9593nnap0d 8954 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (!‘𝐾) # 0)
9694, 95div0apd 8733 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (0 / (!‘𝐾)) = 0)
97 mulcl 7929 . . . . . 6 ((𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ) → (𝑘 · 𝑥) ∈ ℂ)
9897adantl 277 . . . . 5 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ (𝑘 ∈ ℂ ∧ 𝑥 ∈ ℂ)) → (𝑘 · 𝑥) ∈ ℂ)
99 eluzelcn 9528 . . . . . . 7 (𝑘 ∈ (ℤ‘((𝑁𝐾) + 1)) → 𝑘 ∈ ℂ)
10099adantl 277 . . . . . 6 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ 𝑘 ∈ (ℤ‘((𝑁𝐾) + 1))) → 𝑘 ∈ ℂ)
10132, 100eqeltrid 2264 . . . . 5 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ 𝑘 ∈ (ℤ‘((𝑁𝐾) + 1))) → ( I ‘𝑘) ∈ ℂ)
102 simpr 110 . . . . . 6 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ 𝑘 ∈ ℂ) → 𝑘 ∈ ℂ)
103102mul02d 8339 . . . . 5 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ 𝑘 ∈ ℂ) → (0 · 𝑘) = 0)
104102mul01d 8340 . . . . 5 ((((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) ∧ 𝑘 ∈ ℂ) → (𝑘 · 0) = 0)
105 simpr 110 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ¬ 𝐾 ∈ (0...𝑁))
106 nn0uz 9551 . . . . . . . . . . . 12 0 = (ℤ‘0)
10792, 106eleqtrdi 2270 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ (ℤ‘0))
108 simpll 527 . . . . . . . . . . . 12 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℕ0)
109108nn0zd 9362 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℤ)
110 elfz5 10003 . . . . . . . . . . 11 ((𝐾 ∈ (ℤ‘0) ∧ 𝑁 ∈ ℤ) → (𝐾 ∈ (0...𝑁) ↔ 𝐾𝑁))
111107, 109, 110syl2anc 411 . . . . . . . . . 10 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝐾 ∈ (0...𝑁) ↔ 𝐾𝑁))
112 nn0re 9174 . . . . . . . . . . . 12 (𝑁 ∈ ℕ0𝑁 ∈ ℝ)
113112ad2antrr 488 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝑁 ∈ ℝ)
114 nnre 8915 . . . . . . . . . . . 12 (𝐾 ∈ ℕ → 𝐾 ∈ ℝ)
115114ad2antlr 489 . . . . . . . . . . 11 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 𝐾 ∈ ℝ)
116113, 115subge0d 8482 . . . . . . . . . 10 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (0 ≤ (𝑁𝐾) ↔ 𝐾𝑁))
117111, 116bitr4d 191 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝐾 ∈ (0...𝑁) ↔ 0 ≤ (𝑁𝐾)))
118105, 117mtbid 672 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ¬ 0 ≤ (𝑁𝐾))
119 simpl 109 . . . . . . . . . . . 12 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → 𝑁 ∈ ℕ0)
120119nn0zd 9362 . . . . . . . . . . 11 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → 𝑁 ∈ ℤ)
121 simpr 110 . . . . . . . . . . . 12 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → 𝐾 ∈ ℕ)
122121nnzd 9363 . . . . . . . . . . 11 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → 𝐾 ∈ ℤ)
123120, 122zsubcld 9369 . . . . . . . . . 10 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → (𝑁𝐾) ∈ ℤ)
124123adantr 276 . . . . . . . . 9 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) ∈ ℤ)
125 0z 9253 . . . . . . . . 9 0 ∈ ℤ
126 zltnle 9288 . . . . . . . . 9 (((𝑁𝐾) ∈ ℤ ∧ 0 ∈ ℤ) → ((𝑁𝐾) < 0 ↔ ¬ 0 ≤ (𝑁𝐾)))
127124, 125, 126sylancl 413 . . . . . . . 8 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) < 0 ↔ ¬ 0 ≤ (𝑁𝐾)))
128118, 127mpbird 167 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁𝐾) < 0)
129 zltp1le 9296 . . . . . . . 8 (((𝑁𝐾) ∈ ℤ ∧ 0 ∈ ℤ) → ((𝑁𝐾) < 0 ↔ ((𝑁𝐾) + 1) ≤ 0))
130124, 125, 129sylancl 413 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) < 0 ↔ ((𝑁𝐾) + 1) ≤ 0))
131128, 130mpbid 147 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) + 1) ≤ 0)
132 nn0ge0 9190 . . . . . . 7 (𝑁 ∈ ℕ0 → 0 ≤ 𝑁)
133132ad2antrr 488 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 0 ≤ 𝑁)
134 0zd 9254 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 0 ∈ ℤ)
135124peano2zd 9367 . . . . . . 7 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ((𝑁𝐾) + 1) ∈ ℤ)
136 elfz 10001 . . . . . . 7 ((0 ∈ ℤ ∧ ((𝑁𝐾) + 1) ∈ ℤ ∧ 𝑁 ∈ ℤ) → (0 ∈ (((𝑁𝐾) + 1)...𝑁) ↔ (((𝑁𝐾) + 1) ≤ 0 ∧ 0 ≤ 𝑁)))
137134, 135, 109, 136syl3anc 1238 . . . . . 6 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (0 ∈ (((𝑁𝐾) + 1)...𝑁) ↔ (((𝑁𝐾) + 1) ≤ 0 ∧ 0 ≤ 𝑁)))
138131, 133, 137mpbir2and 944 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → 0 ∈ (((𝑁𝐾) + 1)...𝑁))
139 0cn 7940 . . . . . 6 0 ∈ ℂ
140 fvi 5569 . . . . . 6 (0 ∈ ℂ → ( I ‘0) = 0)
141139, 140mp1i 10 . . . . 5 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ( I ‘0) = 0)
14298, 101, 103, 104, 138, 141seq3z 10497 . . . 4 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (seq((𝑁𝐾) + 1)( · , I )‘𝑁) = 0)
143142oveq1d 5884 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)) = (0 / (!‘𝐾)))
144 nnz 9261 . . . . 5 (𝐾 ∈ ℕ → 𝐾 ∈ ℤ)
145 bcval3 10715 . . . . 5 ((𝑁 ∈ ℕ0𝐾 ∈ ℤ ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = 0)
146144, 145syl3an2 1272 . . . 4 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = 0)
1471463expa 1203 . . 3 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = 0)
14896, 143, 1473eqtr4rd 2221 . 2 (((𝑁 ∈ ℕ0𝐾 ∈ ℕ) ∧ ¬ 𝐾 ∈ (0...𝑁)) → (𝑁C𝐾) = ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)))
149 0zd 9254 . . . 4 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → 0 ∈ ℤ)
150 fzdcel 10026 . . . 4 ((𝐾 ∈ ℤ ∧ 0 ∈ ℤ ∧ 𝑁 ∈ ℤ) → DECID 𝐾 ∈ (0...𝑁))
151122, 149, 120, 150syl3anc 1238 . . 3 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → DECID 𝐾 ∈ (0...𝑁))
152 exmiddc 836 . . 3 (DECID 𝐾 ∈ (0...𝑁) → (𝐾 ∈ (0...𝑁) ∨ ¬ 𝐾 ∈ (0...𝑁)))
153151, 152syl 14 . 2 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → (𝐾 ∈ (0...𝑁) ∨ ¬ 𝐾 ∈ (0...𝑁)))
15490, 148, 153mpjaodan 798 1 ((𝑁 ∈ ℕ0𝐾 ∈ ℕ) → (𝑁C𝐾) = ((seq((𝑁𝐾) + 1)( · , I )‘𝑁) / (!‘𝐾)))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 104  wb 105  wo 708  DECID wdc 834  w3a 978   = wceq 1353  wcel 2148  Vcvv 2737   class class class wbr 4000   I cid 4285  cfv 5212  (class class class)co 5869  cc 7800  cr 7801  0cc0 7802  1c1 7803   + caddc 7805   · cmul 7807   < clt 7982  cle 7983  cmin 8118   / cdiv 8618  cn 8908  0cn0 9165  cz 9242  cuz 9517  ...cfz 9995  seqcseq 10431  !cfa 10689  Ccbc 10711
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-13 2150  ax-14 2151  ax-ext 2159  ax-coll 4115  ax-sep 4118  ax-nul 4126  ax-pow 4171  ax-pr 4206  ax-un 4430  ax-setind 4533  ax-iinf 4584  ax-cnex 7893  ax-resscn 7894  ax-1cn 7895  ax-1re 7896  ax-icn 7897  ax-addcl 7898  ax-addrcl 7899  ax-mulcl 7900  ax-mulrcl 7901  ax-addcom 7902  ax-mulcom 7903  ax-addass 7904  ax-mulass 7905  ax-distr 7906  ax-i2m1 7907  ax-0lt1 7908  ax-1rid 7909  ax-0id 7910  ax-rnegex 7911  ax-precex 7912  ax-cnre 7913  ax-pre-ltirr 7914  ax-pre-ltwlin 7915  ax-pre-lttrn 7916  ax-pre-apti 7917  ax-pre-ltadd 7918  ax-pre-mulgt0 7919  ax-pre-mulext 7920
This theorem depends on definitions:  df-bi 117  df-dc 835  df-3or 979  df-3an 980  df-tru 1356  df-fal 1359  df-nf 1461  df-sb 1763  df-eu 2029  df-mo 2030  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ne 2348  df-nel 2443  df-ral 2460  df-rex 2461  df-reu 2462  df-rmo 2463  df-rab 2464  df-v 2739  df-sbc 2963  df-csb 3058  df-dif 3131  df-un 3133  df-in 3135  df-ss 3142  df-nul 3423  df-if 3535  df-pw 3576  df-sn 3597  df-pr 3598  df-op 3600  df-uni 3808  df-int 3843  df-iun 3886  df-br 4001  df-opab 4062  df-mpt 4063  df-tr 4099  df-id 4290  df-po 4293  df-iso 4294  df-iord 4363  df-on 4365  df-ilim 4366  df-suc 4368  df-iom 4587  df-xp 4629  df-rel 4630  df-cnv 4631  df-co 4632  df-dm 4633  df-rn 4634  df-res 4635  df-ima 4636  df-iota 5174  df-fun 5214  df-fn 5215  df-f 5216  df-f1 5217  df-fo 5218  df-f1o 5219  df-fv 5220  df-riota 5825  df-ov 5872  df-oprab 5873  df-mpo 5874  df-1st 6135  df-2nd 6136  df-recs 6300  df-frec 6386  df-pnf 7984  df-mnf 7985  df-xr 7986  df-ltxr 7987  df-le 7988  df-sub 8120  df-neg 8121  df-reap 8522  df-ap 8529  df-div 8619  df-inn 8909  df-n0 9166  df-z 9243  df-uz 9518  df-q 9609  df-fz 9996  df-seqfrec 10432  df-fac 10690  df-bc 10712
This theorem is referenced by:  bcn2  10728
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