| Step | Hyp | Ref
 | Expression | 
| 1 |   | nfcv 2339 | 
. . . 4
⊢
Ⅎ𝑚𝐴 | 
| 2 |   | nfcsb1v 3117 | 
. . . 4
⊢
Ⅎ𝑘⦋𝑚 / 𝑘⦌𝐴 | 
| 3 |   | csbeq1a 3093 | 
. . . 4
⊢ (𝑘 = 𝑚 → 𝐴 = ⦋𝑚 / 𝑘⦌𝐴) | 
| 4 | 1, 2, 3 | cbvprodi 11725 | 
. . 3
⊢
∏𝑘 ∈
{𝑀}𝐴 = ∏𝑚 ∈ {𝑀}⦋𝑚 / 𝑘⦌𝐴 | 
| 5 |   | csbeq1 3087 | 
. . . 4
⊢ (𝑚 = ({〈1, 𝑀〉}‘𝑛) → ⦋𝑚 / 𝑘⦌𝐴 = ⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴) | 
| 6 |   | 1nn 9001 | 
. . . . 5
⊢ 1 ∈
ℕ | 
| 7 | 6 | a1i 9 | 
. . . 4
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → 1 ∈
ℕ) | 
| 8 |   | 1z 9352 | 
. . . . . 6
⊢ 1 ∈
ℤ | 
| 9 |   | f1osng 5545 | 
. . . . . . 7
⊢ ((1
∈ ℤ ∧ 𝑀
∈ 𝑉) → {〈1,
𝑀〉}:{1}–1-1-onto→{𝑀}) | 
| 10 |   | fzsn 10141 | 
. . . . . . . . 9
⊢ (1 ∈
ℤ → (1...1) = {1}) | 
| 11 | 8, 10 | ax-mp 5 | 
. . . . . . . 8
⊢ (1...1) =
{1} | 
| 12 |   | f1oeq2 5493 | 
. . . . . . . 8
⊢ ((1...1)
= {1} → ({〈1, 𝑀〉}:(1...1)–1-1-onto→{𝑀} ↔ {〈1, 𝑀〉}:{1}–1-1-onto→{𝑀})) | 
| 13 | 11, 12 | ax-mp 5 | 
. . . . . . 7
⊢
({〈1, 𝑀〉}:(1...1)–1-1-onto→{𝑀} ↔ {〈1, 𝑀〉}:{1}–1-1-onto→{𝑀}) | 
| 14 | 9, 13 | sylibr 134 | 
. . . . . 6
⊢ ((1
∈ ℤ ∧ 𝑀
∈ 𝑉) → {〈1,
𝑀〉}:(1...1)–1-1-onto→{𝑀}) | 
| 15 | 8, 14 | mpan 424 | 
. . . . 5
⊢ (𝑀 ∈ 𝑉 → {〈1, 𝑀〉}:(1...1)–1-1-onto→{𝑀}) | 
| 16 | 15 | adantr 276 | 
. . . 4
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → {〈1, 𝑀〉}:(1...1)–1-1-onto→{𝑀}) | 
| 17 |   | velsn 3639 | 
. . . . . 6
⊢ (𝑚 ∈ {𝑀} ↔ 𝑚 = 𝑀) | 
| 18 |   | csbeq1 3087 | 
. . . . . . 7
⊢ (𝑚 = 𝑀 → ⦋𝑚 / 𝑘⦌𝐴 = ⦋𝑀 / 𝑘⦌𝐴) | 
| 19 |   | prodsnf.1 | 
. . . . . . . . . 10
⊢
Ⅎ𝑘𝐵 | 
| 20 | 19 | a1i 9 | 
. . . . . . . . 9
⊢ (𝑀 ∈ 𝑉 → Ⅎ𝑘𝐵) | 
| 21 |   | prodsnf.2 | 
. . . . . . . . 9
⊢ (𝑘 = 𝑀 → 𝐴 = 𝐵) | 
| 22 | 20, 21 | csbiegf 3128 | 
. . . . . . . 8
⊢ (𝑀 ∈ 𝑉 → ⦋𝑀 / 𝑘⦌𝐴 = 𝐵) | 
| 23 | 22 | adantr 276 | 
. . . . . . 7
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ⦋𝑀 / 𝑘⦌𝐴 = 𝐵) | 
| 24 | 18, 23 | sylan9eqr 2251 | 
. . . . . 6
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑚 = 𝑀) → ⦋𝑚 / 𝑘⦌𝐴 = 𝐵) | 
| 25 | 17, 24 | sylan2b 287 | 
. . . . 5
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑚 ∈ {𝑀}) → ⦋𝑚 / 𝑘⦌𝐴 = 𝐵) | 
| 26 |   | simplr 528 | 
. . . . 5
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑚 ∈ {𝑀}) → 𝐵 ∈ ℂ) | 
| 27 | 25, 26 | eqeltrd 2273 | 
. . . 4
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑚 ∈ {𝑀}) → ⦋𝑚 / 𝑘⦌𝐴 ∈ ℂ) | 
| 28 | 11 | eleq2i 2263 | 
. . . . . 6
⊢ (𝑛 ∈ (1...1) ↔ 𝑛 ∈ {1}) | 
| 29 |   | velsn 3639 | 
. . . . . 6
⊢ (𝑛 ∈ {1} ↔ 𝑛 = 1) | 
| 30 | 28, 29 | bitri 184 | 
. . . . 5
⊢ (𝑛 ∈ (1...1) ↔ 𝑛 = 1) | 
| 31 |   | fvsng 5758 | 
. . . . . . . . . . 11
⊢ ((1
∈ ℤ ∧ 𝑀
∈ 𝑉) → ({〈1,
𝑀〉}‘1) = 𝑀) | 
| 32 | 8, 31 | mpan 424 | 
. . . . . . . . . 10
⊢ (𝑀 ∈ 𝑉 → ({〈1, 𝑀〉}‘1) = 𝑀) | 
| 33 | 32 | adantr 276 | 
. . . . . . . . 9
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ({〈1, 𝑀〉}‘1) = 𝑀) | 
| 34 | 33 | csbeq1d 3091 | 
. . . . . . . 8
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) →
⦋({〈1, 𝑀〉}‘1) / 𝑘⦌𝐴 = ⦋𝑀 / 𝑘⦌𝐴) | 
| 35 |   | simpr 110 | 
. . . . . . . . 9
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → 𝐵 ∈ ℂ) | 
| 36 |   | fvsng 5758 | 
. . . . . . . . 9
⊢ ((1
∈ ℤ ∧ 𝐵
∈ ℂ) → ({〈1, 𝐵〉}‘1) = 𝐵) | 
| 37 | 8, 35, 36 | sylancr 414 | 
. . . . . . . 8
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ({〈1, 𝐵〉}‘1) = 𝐵) | 
| 38 | 23, 34, 37 | 3eqtr4rd 2240 | 
. . . . . . 7
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ({〈1, 𝐵〉}‘1) =
⦋({〈1, 𝑀〉}‘1) / 𝑘⦌𝐴) | 
| 39 |   | fveq2 5558 | 
. . . . . . . 8
⊢ (𝑛 = 1 → ({〈1, 𝐵〉}‘𝑛) = ({〈1, 𝐵〉}‘1)) | 
| 40 |   | fveq2 5558 | 
. . . . . . . . 9
⊢ (𝑛 = 1 → ({〈1, 𝑀〉}‘𝑛) = ({〈1, 𝑀〉}‘1)) | 
| 41 | 40 | csbeq1d 3091 | 
. . . . . . . 8
⊢ (𝑛 = 1 →
⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴 = ⦋({〈1, 𝑀〉}‘1) / 𝑘⦌𝐴) | 
| 42 | 39, 41 | eqeq12d 2211 | 
. . . . . . 7
⊢ (𝑛 = 1 → (({〈1, 𝐵〉}‘𝑛) = ⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴 ↔ ({〈1, 𝐵〉}‘1) = ⦋({〈1,
𝑀〉}‘1) / 𝑘⦌𝐴)) | 
| 43 | 38, 42 | syl5ibrcom 157 | 
. . . . . 6
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → (𝑛 = 1 → ({〈1, 𝐵〉}‘𝑛) = ⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴)) | 
| 44 | 43 | imp 124 | 
. . . . 5
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑛 = 1) → ({〈1, 𝐵〉}‘𝑛) = ⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴) | 
| 45 | 30, 44 | sylan2b 287 | 
. . . 4
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑛 ∈ (1...1)) → ({〈1, 𝐵〉}‘𝑛) = ⦋({〈1, 𝑀〉}‘𝑛) / 𝑘⦌𝐴) | 
| 46 | 5, 7, 16, 27, 45 | fprodseq 11748 | 
. . 3
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ∏𝑚 ∈ {𝑀}⦋𝑚 / 𝑘⦌𝐴 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1)))‘1)) | 
| 47 | 4, 46 | eqtrid 2241 | 
. 2
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ∏𝑘 ∈ {𝑀}𝐴 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1)))‘1)) | 
| 48 |   | 1zzd 9353 | 
. . . 4
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → 1 ∈
ℤ) | 
| 49 |   | eqid 2196 | 
. . . . . 6
⊢ (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1)) = (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1)) | 
| 50 |   | breq1 4036 | 
. . . . . . 7
⊢ (𝑛 = 𝑗 → (𝑛 ≤ 1 ↔ 𝑗 ≤ 1)) | 
| 51 |   | fveq2 5558 | 
. . . . . . 7
⊢ (𝑛 = 𝑗 → ({〈1, 𝐵〉}‘𝑛) = ({〈1, 𝐵〉}‘𝑗)) | 
| 52 | 50, 51 | ifbieq1d 3583 | 
. . . . . 6
⊢ (𝑛 = 𝑗 → if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1) = if(𝑗 ≤ 1, ({〈1, 𝐵〉}‘𝑗), 1)) | 
| 53 |   | elnnuz 9638 | 
. . . . . . . 8
⊢ (𝑗 ∈ ℕ ↔ 𝑗 ∈
(ℤ≥‘1)) | 
| 54 | 53 | biimpri 133 | 
. . . . . . 7
⊢ (𝑗 ∈
(ℤ≥‘1) → 𝑗 ∈ ℕ) | 
| 55 | 54 | adantl 277 | 
. . . . . 6
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ 𝑗 ∈
ℕ) | 
| 56 |   | simpr 110 | 
. . . . . . . . . . 11
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
𝑗 ≤ 1) | 
| 57 |   | eluzle 9613 | 
. . . . . . . . . . . 12
⊢ (𝑗 ∈
(ℤ≥‘1) → 1 ≤ 𝑗) | 
| 58 | 57 | ad2antlr 489 | 
. . . . . . . . . . 11
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) → 1
≤ 𝑗) | 
| 59 | 54 | nnzd 9447 | 
. . . . . . . . . . . . . 14
⊢ (𝑗 ∈
(ℤ≥‘1) → 𝑗 ∈ ℤ) | 
| 60 | 59 | ad2antlr 489 | 
. . . . . . . . . . . . 13
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
𝑗 ∈
ℤ) | 
| 61 | 60 | zred 9448 | 
. . . . . . . . . . . 12
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
𝑗 ∈
ℝ) | 
| 62 |   | 1red 8041 | 
. . . . . . . . . . . 12
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) → 1
∈ ℝ) | 
| 63 | 61, 62 | letri3d 8142 | 
. . . . . . . . . . 11
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
(𝑗 = 1 ↔ (𝑗 ≤ 1 ∧ 1 ≤ 𝑗))) | 
| 64 | 56, 58, 63 | mpbir2and 946 | 
. . . . . . . . . 10
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
𝑗 = 1) | 
| 65 | 64 | fveq2d 5562 | 
. . . . . . . . 9
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
({〈1, 𝐵〉}‘𝑗) = ({〈1, 𝐵〉}‘1)) | 
| 66 | 37 | ad2antrr 488 | 
. . . . . . . . 9
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
({〈1, 𝐵〉}‘1) = 𝐵) | 
| 67 | 65, 66 | eqtrd 2229 | 
. . . . . . . 8
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
({〈1, 𝐵〉}‘𝑗) = 𝐵) | 
| 68 | 35 | ad2antrr 488 | 
. . . . . . . 8
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
𝐵 ∈
ℂ) | 
| 69 | 67, 68 | eqeltrd 2273 | 
. . . . . . 7
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ 𝑗 ≤ 1) →
({〈1, 𝐵〉}‘𝑗) ∈ ℂ) | 
| 70 |   | 1cnd 8042 | 
. . . . . . 7
⊢ ((((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
∧ ¬ 𝑗 ≤ 1)
→ 1 ∈ ℂ) | 
| 71 | 55 | nnzd 9447 | 
. . . . . . . 8
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ 𝑗 ∈
ℤ) | 
| 72 |   | 1zzd 9353 | 
. . . . . . . 8
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ 1 ∈ ℤ) | 
| 73 |   | zdcle 9402 | 
. . . . . . . 8
⊢ ((𝑗 ∈ ℤ ∧ 1 ∈
ℤ) → DECID 𝑗 ≤ 1) | 
| 74 | 71, 72, 73 | syl2anc 411 | 
. . . . . . 7
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ DECID 𝑗 ≤ 1) | 
| 75 | 69, 70, 74 | ifcldadc 3590 | 
. . . . . 6
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ if(𝑗 ≤ 1,
({〈1, 𝐵〉}‘𝑗), 1) ∈ ℂ) | 
| 76 | 49, 52, 55, 75 | fvmptd3 5655 | 
. . . . 5
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ ((𝑛 ∈ ℕ
↦ if(𝑛 ≤ 1,
({〈1, 𝐵〉}‘𝑛), 1))‘𝑗) = if(𝑗 ≤ 1, ({〈1, 𝐵〉}‘𝑗), 1)) | 
| 77 | 76, 75 | eqeltrd 2273 | 
. . . 4
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ 𝑗 ∈ (ℤ≥‘1))
→ ((𝑛 ∈ ℕ
↦ if(𝑛 ≤ 1,
({〈1, 𝐵〉}‘𝑛), 1))‘𝑗) ∈ ℂ) | 
| 78 |   | mulcl 8006 | 
. . . . 5
⊢ ((𝑗 ∈ ℂ ∧ 𝑞 ∈ ℂ) → (𝑗 · 𝑞) ∈ ℂ) | 
| 79 | 78 | adantl 277 | 
. . . 4
⊢ (((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) ∧ (𝑗 ∈ ℂ ∧ 𝑞 ∈ ℂ)) → (𝑗 · 𝑞) ∈ ℂ) | 
| 80 | 48, 77, 79 | seq3-1 10554 | 
. . 3
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → (seq1( · ,
(𝑛 ∈ ℕ ↦
if(𝑛 ≤ 1, ({〈1,
𝐵〉}‘𝑛), 1)))‘1) = ((𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1))‘1)) | 
| 81 |   | breq1 4036 | 
. . . . . 6
⊢ (𝑛 = 1 → (𝑛 ≤ 1 ↔ 1 ≤ 1)) | 
| 82 | 81, 39 | ifbieq1d 3583 | 
. . . . 5
⊢ (𝑛 = 1 → if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1) = if(1 ≤ 1, ({〈1, 𝐵〉}‘1),
1)) | 
| 83 |   | 1le1 8599 | 
. . . . . . . 8
⊢ 1 ≤
1 | 
| 84 | 83 | iftruei 3567 | 
. . . . . . 7
⊢ if(1 ≤
1, ({〈1, 𝐵〉}‘1), 1) = ({〈1, 𝐵〉}‘1) | 
| 85 | 84, 37 | eqtrid 2241 | 
. . . . . 6
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → if(1 ≤ 1,
({〈1, 𝐵〉}‘1), 1) = 𝐵) | 
| 86 | 85, 35 | eqeltrd 2273 | 
. . . . 5
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → if(1 ≤ 1,
({〈1, 𝐵〉}‘1), 1) ∈
ℂ) | 
| 87 | 49, 82, 7, 86 | fvmptd3 5655 | 
. . . 4
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ((𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1))‘1) = if(1 ≤ 1, ({〈1,
𝐵〉}‘1),
1)) | 
| 88 | 87, 85 | eqtrd 2229 | 
. . 3
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ((𝑛 ∈ ℕ ↦ if(𝑛 ≤ 1, ({〈1, 𝐵〉}‘𝑛), 1))‘1) = 𝐵) | 
| 89 | 80, 88 | eqtrd 2229 | 
. 2
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → (seq1( · ,
(𝑛 ∈ ℕ ↦
if(𝑛 ≤ 1, ({〈1,
𝐵〉}‘𝑛), 1)))‘1) = 𝐵) | 
| 90 | 47, 89 | eqtrd 2229 | 
1
⊢ ((𝑀 ∈ 𝑉 ∧ 𝐵 ∈ ℂ) → ∏𝑘 ∈ {𝑀}𝐴 = 𝐵) |