| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | fsummulc2.2 | . . . 4
⊢ (𝜑 → 𝐶 ∈ ℂ) | 
| 2 | 1 | mul01d 11460 | . . 3
⊢ (𝜑 → (𝐶 · 0) = 0) | 
| 3 |  | sumeq1 15725 | . . . . . 6
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 𝐵 = Σ𝑘 ∈ ∅ 𝐵) | 
| 4 |  | sum0 15757 | . . . . . 6
⊢
Σ𝑘 ∈
∅ 𝐵 =
0 | 
| 5 | 3, 4 | eqtrdi 2793 | . . . . 5
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 𝐵 = 0) | 
| 6 | 5 | oveq2d 7447 | . . . 4
⊢ (𝐴 = ∅ → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = (𝐶 · 0)) | 
| 7 |  | sumeq1 15725 | . . . . 5
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵) = Σ𝑘 ∈ ∅ (𝐶 · 𝐵)) | 
| 8 |  | sum0 15757 | . . . . 5
⊢
Σ𝑘 ∈
∅ (𝐶 · 𝐵) = 0 | 
| 9 | 7, 8 | eqtrdi 2793 | . . . 4
⊢ (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵) = 0) | 
| 10 | 6, 9 | eqeq12d 2753 | . . 3
⊢ (𝐴 = ∅ → ((𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵) ↔ (𝐶 · 0) = 0)) | 
| 11 | 2, 10 | syl5ibrcom 247 | . 2
⊢ (𝜑 → (𝐴 = ∅ → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵))) | 
| 12 |  | addcl 11237 | . . . . . . . . 9
⊢ ((𝑛 ∈ ℂ ∧ 𝑚 ∈ ℂ) → (𝑛 + 𝑚) ∈ ℂ) | 
| 13 | 12 | adantl 481 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ (𝑛 ∈ ℂ ∧ 𝑚 ∈ ℂ)) → (𝑛 + 𝑚) ∈ ℂ) | 
| 14 | 1 | adantr 480 | . . . . . . . . 9
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → 𝐶 ∈ ℂ) | 
| 15 |  | adddi 11244 | . . . . . . . . . 10
⊢ ((𝐶 ∈ ℂ ∧ 𝑛 ∈ ℂ ∧ 𝑚 ∈ ℂ) → (𝐶 · (𝑛 + 𝑚)) = ((𝐶 · 𝑛) + (𝐶 · 𝑚))) | 
| 16 | 15 | 3expb 1121 | . . . . . . . . 9
⊢ ((𝐶 ∈ ℂ ∧ (𝑛 ∈ ℂ ∧ 𝑚 ∈ ℂ)) → (𝐶 · (𝑛 + 𝑚)) = ((𝐶 · 𝑛) + (𝐶 · 𝑚))) | 
| 17 | 14, 16 | sylan 580 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ (𝑛 ∈ ℂ ∧ 𝑚 ∈ ℂ)) → (𝐶 · (𝑛 + 𝑚)) = ((𝐶 · 𝑛) + (𝐶 · 𝑚))) | 
| 18 |  | simprl 771 | . . . . . . . . 9
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (♯‘𝐴) ∈
ℕ) | 
| 19 |  | nnuz 12921 | . . . . . . . . 9
⊢ ℕ =
(ℤ≥‘1) | 
| 20 | 18, 19 | eleqtrdi 2851 | . . . . . . . 8
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (♯‘𝐴) ∈
(ℤ≥‘1)) | 
| 21 |  | fsummulc2.3 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐵 ∈ ℂ) | 
| 22 | 21 | fmpttd 7135 | . . . . . . . . . . 11
⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶ℂ) | 
| 23 | 22 | ad2antrr 726 | . . . . . . . . . 10
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶ℂ) | 
| 24 |  | simprr 773 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) | 
| 25 | 24 | adantr 480 | . . . . . . . . . . 11
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) | 
| 26 |  | f1of 6848 | . . . . . . . . . . 11
⊢ (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → 𝑓:(1...(♯‘𝐴))⟶𝐴) | 
| 27 | 25, 26 | syl 17 | . . . . . . . . . 10
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → 𝑓:(1...(♯‘𝐴))⟶𝐴) | 
| 28 |  | fco 6760 | . . . . . . . . . 10
⊢ (((𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶ℂ ∧ 𝑓:(1...(♯‘𝐴))⟶𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓):(1...(♯‘𝐴))⟶ℂ) | 
| 29 | 23, 27, 28 | syl2anc 584 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓):(1...(♯‘𝐴))⟶ℂ) | 
| 30 |  | simpr 484 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → 𝑛 ∈ (1...(♯‘𝐴))) | 
| 31 | 29, 30 | ffvelcdmd 7105 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑛) ∈ ℂ) | 
| 32 | 27, 30 | ffvelcdmd 7105 | . . . . . . . . . 10
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (𝑓‘𝑛) ∈ 𝐴) | 
| 33 |  | simpr 484 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝑘 ∈ 𝐴) | 
| 34 | 1 | adantr 480 | . . . . . . . . . . . . . . 15
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐶 ∈ ℂ) | 
| 35 | 34, 21 | mulcld 11281 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → (𝐶 · 𝐵) ∈ ℂ) | 
| 36 |  | eqid 2737 | . . . . . . . . . . . . . . 15
⊢ (𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) = (𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) | 
| 37 | 36 | fvmpt2 7027 | . . . . . . . . . . . . . 14
⊢ ((𝑘 ∈ 𝐴 ∧ (𝐶 · 𝐵) ∈ ℂ) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · 𝐵)) | 
| 38 | 33, 35, 37 | syl2anc 584 | . . . . . . . . . . . . 13
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · 𝐵)) | 
| 39 |  | eqid 2737 | . . . . . . . . . . . . . . . 16
⊢ (𝑘 ∈ 𝐴 ↦ 𝐵) = (𝑘 ∈ 𝐴 ↦ 𝐵) | 
| 40 | 39 | fvmpt2 7027 | . . . . . . . . . . . . . . 15
⊢ ((𝑘 ∈ 𝐴 ∧ 𝐵 ∈ ℂ) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘) = 𝐵) | 
| 41 | 33, 21, 40 | syl2anc 584 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘) = 𝐵) | 
| 42 | 41 | oveq2d 7447 | . . . . . . . . . . . . 13
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘)) = (𝐶 · 𝐵)) | 
| 43 | 38, 42 | eqtr4d 2780 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘))) | 
| 44 | 43 | ralrimiva 3146 | . . . . . . . . . . 11
⊢ (𝜑 → ∀𝑘 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘))) | 
| 45 | 44 | ad2antrr 726 | . . . . . . . . . 10
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → ∀𝑘 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘))) | 
| 46 |  | nffvmpt1 6917 | . . . . . . . . . . . 12
⊢
Ⅎ𝑘((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛)) | 
| 47 |  | nfcv 2905 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑘𝐶 | 
| 48 |  | nfcv 2905 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑘
· | 
| 49 |  | nffvmpt1 6917 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑘((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛)) | 
| 50 | 47, 48, 49 | nfov 7461 | . . . . . . . . . . . 12
⊢
Ⅎ𝑘(𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 51 | 46, 50 | nfeq 2919 | . . . . . . . . . . 11
⊢
Ⅎ𝑘((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 52 |  | fveq2 6906 | . . . . . . . . . . . 12
⊢ (𝑘 = (𝑓‘𝑛) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛))) | 
| 53 |  | fveq2 6906 | . . . . . . . . . . . . 13
⊢ (𝑘 = (𝑓‘𝑛) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 54 | 53 | oveq2d 7447 | . . . . . . . . . . . 12
⊢ (𝑘 = (𝑓‘𝑛) → (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛)))) | 
| 55 | 52, 54 | eqeq12d 2753 | . . . . . . . . . . 11
⊢ (𝑘 = (𝑓‘𝑛) → (((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘)) ↔ ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))))) | 
| 56 | 51, 55 | rspc 3610 | . . . . . . . . . 10
⊢ ((𝑓‘𝑛) ∈ 𝐴 → (∀𝑘 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑘) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑘)) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))))) | 
| 57 | 32, 45, 56 | sylc 65 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛)))) | 
| 58 | 26 | ad2antll 729 | . . . . . . . . . 10
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → 𝑓:(1...(♯‘𝐴))⟶𝐴) | 
| 59 |  | fvco3 7008 | . . . . . . . . . 10
⊢ ((𝑓:(1...(♯‘𝐴))⟶𝐴 ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) ∘ 𝑓)‘𝑛) = ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛))) | 
| 60 | 58, 59 | sylan 580 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) ∘ 𝑓)‘𝑛) = ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛))) | 
| 61 |  | fvco3 7008 | . . . . . . . . . . 11
⊢ ((𝑓:(1...(♯‘𝐴))⟶𝐴 ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑛) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 62 | 58, 61 | sylan 580 | . . . . . . . . . 10
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑛) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 63 | 62 | oveq2d 7447 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (𝐶 · (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑛)) = (𝐶 · ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛)))) | 
| 64 | 57, 60, 63 | 3eqtr4d 2787 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑛 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) ∘ 𝑓)‘𝑛) = (𝐶 · (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑛))) | 
| 65 | 13, 17, 20, 31, 64 | seqdistr 14094 | . . . . . . 7
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (seq1( + , ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) ∘ 𝑓))‘(♯‘𝐴)) = (𝐶 · (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴)))) | 
| 66 |  | fveq2 6906 | . . . . . . . 8
⊢ (𝑚 = (𝑓‘𝑛) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑚) = ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘(𝑓‘𝑛))) | 
| 67 | 35 | fmpttd 7135 | . . . . . . . . . 10
⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)):𝐴⟶ℂ) | 
| 68 | 67 | adantr 480 | . . . . . . . . 9
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)):𝐴⟶ℂ) | 
| 69 | 68 | ffvelcdmda 7104 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑚 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑚) ∈ ℂ) | 
| 70 | 66, 18, 24, 69, 60 | fsum 15756 | . . . . . . 7
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑚) = (seq1( + , ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵)) ∘ 𝑓))‘(♯‘𝐴))) | 
| 71 |  | fveq2 6906 | . . . . . . . . 9
⊢ (𝑚 = (𝑓‘𝑛) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑛))) | 
| 72 | 22 | adantr 480 | . . . . . . . . . 10
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶ℂ) | 
| 73 | 72 | ffvelcdmda 7104 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑚 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) ∈ ℂ) | 
| 74 | 71, 18, 24, 73, 62 | fsum 15756 | . . . . . . . 8
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴))) | 
| 75 | 74 | oveq2d 7447 | . . . . . . 7
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝐶 · Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚)) = (𝐶 · (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴)))) | 
| 76 | 65, 70, 75 | 3eqtr4rd 2788 | . . . . . 6
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝐶 · Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚)) = Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑚)) | 
| 77 |  | sumfc 15745 | . . . . . . 7
⊢
Σ𝑚 ∈
𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = Σ𝑘 ∈ 𝐴 𝐵 | 
| 78 | 77 | oveq2i 7442 | . . . . . 6
⊢ (𝐶 · Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚)) = (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) | 
| 79 |  | sumfc 15745 | . . . . . 6
⊢
Σ𝑚 ∈
𝐴 ((𝑘 ∈ 𝐴 ↦ (𝐶 · 𝐵))‘𝑚) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵) | 
| 80 | 76, 78, 79 | 3eqtr3g 2800 | . . . . 5
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵)) | 
| 81 | 80 | expr 456 | . . . 4
⊢ ((𝜑 ∧ (♯‘𝐴) ∈ ℕ) → (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵))) | 
| 82 | 81 | exlimdv 1933 | . . 3
⊢ ((𝜑 ∧ (♯‘𝐴) ∈ ℕ) →
(∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵))) | 
| 83 | 82 | expimpd 453 | . 2
⊢ (𝜑 → (((♯‘𝐴) ∈ ℕ ∧
∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵))) | 
| 84 |  | fsummulc2.1 | . . 3
⊢ (𝜑 → 𝐴 ∈ Fin) | 
| 85 |  | fz1f1o 15746 | . . 3
⊢ (𝐴 ∈ Fin → (𝐴 = ∅ ∨
((♯‘𝐴) ∈
ℕ ∧ ∃𝑓
𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴))) | 
| 86 | 84, 85 | syl 17 | . 2
⊢ (𝜑 → (𝐴 = ∅ ∨ ((♯‘𝐴) ∈ ℕ ∧
∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴))) | 
| 87 | 11, 83, 86 | mpjaod 861 | 1
⊢ (𝜑 → (𝐶 · Σ𝑘 ∈ 𝐴 𝐵) = Σ𝑘 ∈ 𝐴 (𝐶 · 𝐵)) |