| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | fsumcl2lem.5 | . . . 4
⊢ (𝜑 → 𝐴 ≠ ∅) | 
| 2 | 1 | a1d 25 | . . 3
⊢ (𝜑 → (¬ Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆 → 𝐴 ≠ ∅)) | 
| 3 | 2 | necon4bd 2959 | . 2
⊢ (𝜑 → (𝐴 = ∅ → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆)) | 
| 4 |  | sumfc 15746 | . . . . . . 7
⊢
Σ𝑚 ∈
𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = Σ𝑘 ∈ 𝐴 𝐵 | 
| 5 |  | fveq2 6905 | . . . . . . . 8
⊢ (𝑚 = (𝑓‘𝑥) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑥))) | 
| 6 |  | simprl 770 | . . . . . . . 8
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (♯‘𝐴) ∈
ℕ) | 
| 7 |  | simprr 772 | . . . . . . . 8
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) | 
| 8 |  | fsumcllem.1 | . . . . . . . . . 10
⊢ (𝜑 → 𝑆 ⊆ ℂ) | 
| 9 | 8 | ad2antrr 726 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑚 ∈ 𝐴) → 𝑆 ⊆ ℂ) | 
| 10 |  | fsumcllem.4 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐵 ∈ 𝑆) | 
| 11 | 10 | fmpttd 7134 | . . . . . . . . . . 11
⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶𝑆) | 
| 12 | 11 | adantr 480 | . . . . . . . . . 10
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶𝑆) | 
| 13 | 12 | ffvelcdmda 7103 | . . . . . . . . 9
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑚 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) ∈ 𝑆) | 
| 14 | 9, 13 | sseldd 3983 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑚 ∈ 𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) ∈ ℂ) | 
| 15 |  | f1of 6847 | . . . . . . . . . 10
⊢ (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → 𝑓:(1...(♯‘𝐴))⟶𝐴) | 
| 16 | 7, 15 | syl 17 | . . . . . . . . 9
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → 𝑓:(1...(♯‘𝐴))⟶𝐴) | 
| 17 |  | fvco3 7007 | . . . . . . . . 9
⊢ ((𝑓:(1...(♯‘𝐴))⟶𝐴 ∧ 𝑥 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑥) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑥))) | 
| 18 | 16, 17 | sylan 580 | . . . . . . . 8
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑥 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑥) = ((𝑘 ∈ 𝐴 ↦ 𝐵)‘(𝑓‘𝑥))) | 
| 19 | 5, 6, 7, 14, 18 | fsum 15757 | . . . . . . 7
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑚 ∈ 𝐴 ((𝑘 ∈ 𝐴 ↦ 𝐵)‘𝑚) = (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴))) | 
| 20 | 4, 19 | eqtr3id 2790 | . . . . . 6
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑘 ∈ 𝐴 𝐵 = (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴))) | 
| 21 |  | nnuz 12922 | . . . . . . . 8
⊢ ℕ =
(ℤ≥‘1) | 
| 22 | 6, 21 | eleqtrdi 2850 | . . . . . . 7
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (♯‘𝐴) ∈
(ℤ≥‘1)) | 
| 23 |  | fco 6759 | . . . . . . . . 9
⊢ (((𝑘 ∈ 𝐴 ↦ 𝐵):𝐴⟶𝑆 ∧ 𝑓:(1...(♯‘𝐴))⟶𝐴) → ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓):(1...(♯‘𝐴))⟶𝑆) | 
| 24 | 12, 16, 23 | syl2anc 584 | . . . . . . . 8
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓):(1...(♯‘𝐴))⟶𝑆) | 
| 25 | 24 | ffvelcdmda 7103 | . . . . . . 7
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ 𝑥 ∈ (1...(♯‘𝐴))) → (((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓)‘𝑥) ∈ 𝑆) | 
| 26 |  | fsumcllem.2 | . . . . . . . 8
⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝑦 ∈ 𝑆)) → (𝑥 + 𝑦) ∈ 𝑆) | 
| 27 | 26 | adantlr 715 | . . . . . . 7
⊢ (((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) ∧ (𝑥 ∈ 𝑆 ∧ 𝑦 ∈ 𝑆)) → (𝑥 + 𝑦) ∈ 𝑆) | 
| 28 | 22, 25, 27 | seqcl 14064 | . . . . . 6
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → (seq1( + , ((𝑘 ∈ 𝐴 ↦ 𝐵) ∘ 𝑓))‘(♯‘𝐴)) ∈ 𝑆) | 
| 29 | 20, 28 | eqeltrd 2840 | . . . . 5
⊢ ((𝜑 ∧ ((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆) | 
| 30 | 29 | expr 456 | . . . 4
⊢ ((𝜑 ∧ (♯‘𝐴) ∈ ℕ) → (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆)) | 
| 31 | 30 | exlimdv 1932 | . . 3
⊢ ((𝜑 ∧ (♯‘𝐴) ∈ ℕ) →
(∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆)) | 
| 32 | 31 | expimpd 453 | . 2
⊢ (𝜑 → (((♯‘𝐴) ∈ ℕ ∧
∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆)) | 
| 33 |  | fsumcllem.3 | . . 3
⊢ (𝜑 → 𝐴 ∈ Fin) | 
| 34 |  | fz1f1o 15747 | . . 3
⊢ (𝐴 ∈ Fin → (𝐴 = ∅ ∨
((♯‘𝐴) ∈
ℕ ∧ ∃𝑓
𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴))) | 
| 35 | 33, 34 | syl 17 | . 2
⊢ (𝜑 → (𝐴 = ∅ ∨ ((♯‘𝐴) ∈ ℕ ∧
∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴))) | 
| 36 | 3, 32, 35 | mpjaod 860 | 1
⊢ (𝜑 → Σ𝑘 ∈ 𝐴 𝐵 ∈ 𝑆) |