| Step | Hyp | Ref
 | Expression | 
| 1 |   | eqid 2196 | 
. . . 4
⊢
(ℤ≥‘𝑀) = (ℤ≥‘𝑀) | 
| 2 |   | simp1 999 | 
. . . 4
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → 𝑀 ∈ ℤ) | 
| 3 |   | simp2 1000 | 
. . . 4
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → 𝐴 ⊆ (ℤ≥‘𝑀)) | 
| 4 |   | c0ex 8020 | 
. . . . . . 7
⊢ 0 ∈
V | 
| 5 | 4 | fvconst2 5778 | 
. . . . . 6
⊢ (𝑘 ∈
(ℤ≥‘𝑀) →
(((ℤ≥‘𝑀) × {0})‘𝑘) = 0) | 
| 6 | 5 | adantl 277 | 
. . . . 5
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) →
(((ℤ≥‘𝑀) × {0})‘𝑘) = 0) | 
| 7 |   | eleq1w 2257 | 
. . . . . . . 8
⊢ (𝑗 = 𝑘 → (𝑗 ∈ 𝐴 ↔ 𝑘 ∈ 𝐴)) | 
| 8 | 7 | dcbid 839 | 
. . . . . . 7
⊢ (𝑗 = 𝑘 → (DECID 𝑗 ∈ 𝐴 ↔ DECID 𝑘 ∈ 𝐴)) | 
| 9 |   | simpl3 1004 | 
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → ∀𝑗 ∈
(ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) | 
| 10 |   | simpr 110 | 
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → 𝑘 ∈ (ℤ≥‘𝑀)) | 
| 11 | 8, 9, 10 | rspcdva 2873 | 
. . . . . 6
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → DECID
𝑘 ∈ 𝐴) | 
| 12 |   | ifiddc 3595 | 
. . . . . 6
⊢
(DECID 𝑘 ∈ 𝐴 → if(𝑘 ∈ 𝐴, 0, 0) = 0) | 
| 13 | 11, 12 | syl 14 | 
. . . . 5
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → if(𝑘 ∈ 𝐴, 0, 0) = 0) | 
| 14 | 6, 13 | eqtr4d 2232 | 
. . . 4
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) →
(((ℤ≥‘𝑀) × {0})‘𝑘) = if(𝑘 ∈ 𝐴, 0, 0)) | 
| 15 |   | simp3 1001 | 
. . . . 5
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) | 
| 16 |   | eleq1w 2257 | 
. . . . . . 7
⊢ (𝑗 = 𝑎 → (𝑗 ∈ 𝐴 ↔ 𝑎 ∈ 𝐴)) | 
| 17 | 16 | dcbid 839 | 
. . . . . 6
⊢ (𝑗 = 𝑎 → (DECID 𝑗 ∈ 𝐴 ↔ DECID 𝑎 ∈ 𝐴)) | 
| 18 | 17 | cbvralv 2729 | 
. . . . 5
⊢
(∀𝑗 ∈
(ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴 ↔ ∀𝑎 ∈ (ℤ≥‘𝑀)DECID 𝑎 ∈ 𝐴) | 
| 19 | 15, 18 | sylib 122 | 
. . . 4
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ∀𝑎 ∈ (ℤ≥‘𝑀)DECID 𝑎 ∈ 𝐴) | 
| 20 |   | 0cnd 8019 | 
. . . 4
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ 𝐴) → 0 ∈ ℂ) | 
| 21 | 1, 2, 3, 14, 19, 20 | zsumdc 11549 | 
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → Σ𝑘 ∈ 𝐴 0 = ( ⇝ ‘seq𝑀( + , ((ℤ≥‘𝑀) ×
{0})))) | 
| 22 |   | fclim 11459 | 
. . . . 5
⊢  ⇝
:dom ⇝ ⟶ℂ | 
| 23 |   | ffun 5410 | 
. . . . 5
⊢ ( ⇝
:dom ⇝ ⟶ℂ → Fun ⇝ ) | 
| 24 | 22, 23 | ax-mp 5 | 
. . . 4
⊢ Fun
⇝ | 
| 25 |   | serclim0 11470 | 
. . . . 5
⊢ (𝑀 ∈ ℤ → seq𝑀( + ,
((ℤ≥‘𝑀) × {0})) ⇝ 0) | 
| 26 | 2, 25 | syl 14 | 
. . . 4
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → seq𝑀( + , ((ℤ≥‘𝑀) × {0})) ⇝
0) | 
| 27 |   | funbrfv 5599 | 
. . . 4
⊢ (Fun
⇝ → (seq𝑀( + ,
((ℤ≥‘𝑀) × {0})) ⇝ 0 → ( ⇝
‘seq𝑀( + ,
((ℤ≥‘𝑀) × {0}))) = 0)) | 
| 28 | 24, 26, 27 | mpsyl 65 | 
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ( ⇝ ‘seq𝑀( + ,
((ℤ≥‘𝑀) × {0}))) = 0) | 
| 29 | 21, 28 | eqtrd 2229 | 
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 30 |   | fz1f1o 11540 | 
. . 3
⊢ (𝐴 ∈ Fin → (𝐴 = ∅ ∨
((♯‘𝐴) ∈
ℕ ∧ ∃𝑓
𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴))) | 
| 31 |   | sumeq1 11520 | 
. . . . 5
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 0 = Σ𝑘 ∈ ∅ 0) | 
| 32 |   | sum0 11553 | 
. . . . 5
⊢
Σ𝑘 ∈
∅ 0 = 0 | 
| 33 | 31, 32 | eqtrdi 2245 | 
. . . 4
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 34 |   | eqidd 2197 | 
. . . . . . . . 9
⊢ (𝑘 = (𝑓‘𝑛) → 0 = 0) | 
| 35 |   | simpl 109 | 
. . . . . . . . 9
⊢
(((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (♯‘𝐴) ∈
ℕ) | 
| 36 |   | simpr 110 | 
. . . . . . . . 9
⊢
(((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) | 
| 37 |   | 0cnd 8019 | 
. . . . . . . . 9
⊢
((((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) ∧ 𝑘 ∈ 𝐴) → 0 ∈ ℂ) | 
| 38 |   | elfznn 10129 | 
. . . . . . . . . . 11
⊢ (𝑛 ∈
(1...(♯‘𝐴))
→ 𝑛 ∈
ℕ) | 
| 39 | 4 | fvconst2 5778 | 
. . . . . . . . . . 11
⊢ (𝑛 ∈ ℕ → ((ℕ
× {0})‘𝑛) =
0) | 
| 40 | 38, 39 | syl 14 | 
. . . . . . . . . 10
⊢ (𝑛 ∈
(1...(♯‘𝐴))
→ ((ℕ × {0})‘𝑛) = 0) | 
| 41 | 40 | adantl 277 | 
. . . . . . . . 9
⊢
((((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → ((ℕ ×
{0})‘𝑛) =
0) | 
| 42 | 34, 35, 36, 37, 41 | fsum3 11552 | 
. . . . . . . 8
⊢
(((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → Σ𝑘 ∈ 𝐴 0 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ (♯‘𝐴), ((ℕ × {0})‘𝑛),
0)))‘(♯‘𝐴))) | 
| 43 |   | nnuz 9637 | 
. . . . . . . . . . . . 13
⊢ ℕ =
(ℤ≥‘1) | 
| 44 | 43 | fser0const 10627 | 
. . . . . . . . . . . 12
⊢
((♯‘𝐴)
∈ ℕ → (𝑛
∈ ℕ ↦ if(𝑛
≤ (♯‘𝐴),
((ℕ × {0})‘𝑛), 0)) = (ℕ ×
{0})) | 
| 45 | 44 | seqeq3d 10547 | 
. . . . . . . . . . 11
⊢
((♯‘𝐴)
∈ ℕ → seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ (♯‘𝐴), ((ℕ × {0})‘𝑛), 0))) = seq1( + , (ℕ
× {0}))) | 
| 46 | 45 | fveq1d 5560 | 
. . . . . . . . . 10
⊢
((♯‘𝐴)
∈ ℕ → (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ (♯‘𝐴), ((ℕ × {0})‘𝑛),
0)))‘(♯‘𝐴)) = (seq1( + , (ℕ ×
{0}))‘(♯‘𝐴))) | 
| 47 | 43 | ser0 10625 | 
. . . . . . . . . 10
⊢
((♯‘𝐴)
∈ ℕ → (seq1( + , (ℕ ×
{0}))‘(♯‘𝐴)) = 0) | 
| 48 | 46, 47 | eqtrd 2229 | 
. . . . . . . . 9
⊢
((♯‘𝐴)
∈ ℕ → (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ (♯‘𝐴), ((ℕ × {0})‘𝑛),
0)))‘(♯‘𝐴)) = 0) | 
| 49 | 35, 48 | syl 14 | 
. . . . . . . 8
⊢
(((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ (♯‘𝐴), ((ℕ ×
{0})‘𝑛),
0)))‘(♯‘𝐴)) = 0) | 
| 50 | 42, 49 | eqtrd 2229 | 
. . . . . . 7
⊢
(((♯‘𝐴)
∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 51 | 50 | ex 115 | 
. . . . . 6
⊢
((♯‘𝐴)
∈ ℕ → (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → Σ𝑘 ∈ 𝐴 0 = 0)) | 
| 52 | 51 | exlimdv 1833 | 
. . . . 5
⊢
((♯‘𝐴)
∈ ℕ → (∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → Σ𝑘 ∈ 𝐴 0 = 0)) | 
| 53 | 52 | imp 124 | 
. . . 4
⊢
(((♯‘𝐴)
∈ ℕ ∧ ∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 54 | 33, 53 | jaoi 717 | 
. . 3
⊢ ((𝐴 = ∅ ∨
((♯‘𝐴) ∈
ℕ ∧ ∃𝑓
𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 55 | 30, 54 | syl 14 | 
. 2
⊢ (𝐴 ∈ Fin → Σ𝑘 ∈ 𝐴 0 = 0) | 
| 56 | 29, 55 | jaoi 717 | 
1
⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆
(ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∨ 𝐴 ∈ Fin) → Σ𝑘 ∈ 𝐴 0 = 0) |