| Step | Hyp | Ref
 | Expression | 
| 1 |   | elnnuz 9638 | 
. . . . 5
⊢ (𝑁 ∈ ℕ ↔ 𝑁 ∈
(ℤ≥‘1)) | 
| 2 | 1 | biimpi 120 | 
. . . 4
⊢ (𝑁 ∈ ℕ → 𝑁 ∈
(ℤ≥‘1)) | 
| 3 | 2 | adantr 276 | 
. . 3
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝑁 ∈
(ℤ≥‘1)) | 
| 4 |   | mulgnngsum.f | 
. . . . . 6
⊢ 𝐹 = (𝑥 ∈ (1...𝑁) ↦ 𝑋) | 
| 5 | 4 | a1i 9 | 
. . . . 5
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → 𝐹 = (𝑥 ∈ (1...𝑁) ↦ 𝑋)) | 
| 6 |   | eqidd 2197 | 
. . . . 5
⊢ ((((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) ∧ 𝑥 = 𝑖) → 𝑋 = 𝑋) | 
| 7 |   | simpr 110 | 
. . . . 5
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → 𝑖 ∈ (1...𝑁)) | 
| 8 |   | simpr 110 | 
. . . . . 6
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝑋 ∈ 𝐵) | 
| 9 | 8 | adantr 276 | 
. . . . 5
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → 𝑋 ∈ 𝐵) | 
| 10 | 5, 6, 7, 9 | fvmptd 5642 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → (𝐹‘𝑖) = 𝑋) | 
| 11 |   | elfznn 10129 | 
. . . . 5
⊢ (𝑖 ∈ (1...𝑁) → 𝑖 ∈ ℕ) | 
| 12 |   | fvconst2g 5776 | 
. . . . 5
⊢ ((𝑋 ∈ 𝐵 ∧ 𝑖 ∈ ℕ) → ((ℕ ×
{𝑋})‘𝑖) = 𝑋) | 
| 13 | 8, 11, 12 | syl2an 289 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → ((ℕ × {𝑋})‘𝑖) = 𝑋) | 
| 14 | 10, 13 | eqtr4d 2232 | 
. . 3
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑖 ∈ (1...𝑁)) → (𝐹‘𝑖) = ((ℕ × {𝑋})‘𝑖)) | 
| 15 |   | 1zzd 9353 | 
. . . . . . 7
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 1 ∈ ℤ) | 
| 16 |   | nnz 9345 | 
. . . . . . . 8
⊢ (𝑁 ∈ ℕ → 𝑁 ∈
ℤ) | 
| 17 | 16 | adantr 276 | 
. . . . . . 7
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝑁 ∈ ℤ) | 
| 18 | 15, 17 | fzfigd 10523 | 
. . . . . 6
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (1...𝑁) ∈ Fin) | 
| 19 |   | mptexg 5787 | 
. . . . . . 7
⊢
((1...𝑁) ∈ Fin
→ (𝑥 ∈ (1...𝑁) ↦ 𝑋) ∈ V) | 
| 20 | 4, 19 | eqeltrid 2283 | 
. . . . . 6
⊢
((1...𝑁) ∈ Fin
→ 𝐹 ∈
V) | 
| 21 | 18, 20 | syl 14 | 
. . . . 5
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝐹 ∈ V) | 
| 22 | 21 | adantr 276 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ 𝐹 ∈
V) | 
| 23 |   | vex 2766 | 
. . . 4
⊢ 𝑎 ∈ V | 
| 24 |   | fvexg 5577 | 
. . . 4
⊢ ((𝐹 ∈ V ∧ 𝑎 ∈ V) → (𝐹‘𝑎) ∈ V) | 
| 25 | 22, 23, 24 | sylancl 413 | 
. . 3
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ (𝐹‘𝑎) ∈ V) | 
| 26 |   | nnex 8996 | 
. . . . 5
⊢ ℕ
∈ V | 
| 27 | 8 | adantr 276 | 
. . . . . 6
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ 𝑋 ∈ 𝐵) | 
| 28 |   | snexg 4217 | 
. . . . . 6
⊢ (𝑋 ∈ 𝐵 → {𝑋} ∈ V) | 
| 29 | 27, 28 | syl 14 | 
. . . . 5
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ {𝑋} ∈
V) | 
| 30 |   | xpexg 4777 | 
. . . . 5
⊢ ((ℕ
∈ V ∧ {𝑋} ∈
V) → (ℕ × {𝑋}) ∈ V) | 
| 31 | 26, 29, 30 | sylancr 414 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ (ℕ × {𝑋}) ∈ V) | 
| 32 |   | fvexg 5577 | 
. . . 4
⊢
(((ℕ × {𝑋}) ∈ V ∧ 𝑎 ∈ V) → ((ℕ × {𝑋})‘𝑎) ∈ V) | 
| 33 | 31, 23, 32 | sylancl 413 | 
. . 3
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑎 ∈ (ℤ≥‘1))
→ ((ℕ × {𝑋})‘𝑎) ∈ V) | 
| 34 |   | mulgnngsum.b | 
. . . . . . 7
⊢ 𝐵 = (Base‘𝐺) | 
| 35 | 34 | basmex 12737 | 
. . . . . 6
⊢ (𝑋 ∈ 𝐵 → 𝐺 ∈ V) | 
| 36 | 35 | adantl 277 | 
. . . . 5
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝐺 ∈ V) | 
| 37 |   | plusgslid 12790 | 
. . . . . 6
⊢
(+g = Slot (+g‘ndx) ∧
(+g‘ndx) ∈ ℕ) | 
| 38 | 37 | slotex 12705 | 
. . . . 5
⊢ (𝐺 ∈ V →
(+g‘𝐺)
∈ V) | 
| 39 | 36, 38 | syl 14 | 
. . . 4
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (+g‘𝐺) ∈ V) | 
| 40 |   | simprr 531 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ (𝑎 ∈ V ∧ 𝑏 ∈ V)) → 𝑏 ∈ V) | 
| 41 |   | ovexg 5956 | 
. . . 4
⊢ ((𝑎 ∈ V ∧
(+g‘𝐺)
∈ V ∧ 𝑏 ∈ V)
→ (𝑎(+g‘𝐺)𝑏) ∈ V) | 
| 42 | 23, 39, 40, 41 | mp3an2ani 1355 | 
. . 3
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ (𝑎 ∈ V ∧ 𝑏 ∈ V)) → (𝑎(+g‘𝐺)𝑏) ∈ V) | 
| 43 | 3, 14, 25, 33, 42 | seq3fveq 10571 | 
. 2
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (seq1((+g‘𝐺), 𝐹)‘𝑁) = (seq1((+g‘𝐺), (ℕ × {𝑋}))‘𝑁)) | 
| 44 |   | eqid 2196 | 
. . 3
⊢
(+g‘𝐺) = (+g‘𝐺) | 
| 45 | 8 | adantr 276 | 
. . . 4
⊢ (((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) ∧ 𝑥 ∈ (1...𝑁)) → 𝑋 ∈ 𝐵) | 
| 46 | 45, 4 | fmptd 5716 | 
. . 3
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → 𝐹:(1...𝑁)⟶𝐵) | 
| 47 | 34, 44, 36, 3, 46 | gsumval2 13040 | 
. 2
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (𝐺 Σg 𝐹) =
(seq1((+g‘𝐺), 𝐹)‘𝑁)) | 
| 48 |   | mulgnngsum.t | 
. . 3
⊢  · =
(.g‘𝐺) | 
| 49 |   | eqid 2196 | 
. . 3
⊢
seq1((+g‘𝐺), (ℕ × {𝑋})) = seq1((+g‘𝐺), (ℕ × {𝑋})) | 
| 50 | 34, 44, 48, 49 | mulgnn 13256 | 
. 2
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (𝑁 · 𝑋) = (seq1((+g‘𝐺), (ℕ × {𝑋}))‘𝑁)) | 
| 51 | 43, 47, 50 | 3eqtr4rd 2240 | 
1
⊢ ((𝑁 ∈ ℕ ∧ 𝑋 ∈ 𝐵) → (𝑁 · 𝑋) = (𝐺 Σg 𝐹)) |