| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | hadcoma 1598 | . . . 4
⊢
(hadd(𝑘 ∈ 𝐴, 𝑘 ∈ 𝐵, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘)) ↔
hadd(𝑘 ∈ 𝐵, 𝑘 ∈ 𝐴, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘))) | 
| 2 | 1 | a1i 11 | . . 3
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → (hadd(𝑘 ∈ 𝐴, 𝑘 ∈ 𝐵, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘)) ↔
hadd(𝑘 ∈ 𝐵, 𝑘 ∈ 𝐴, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘)))) | 
| 3 | 2 | rabbidv 3443 | . 2
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → {𝑘 ∈ ℕ0 ∣
hadd(𝑘 ∈ 𝐴, 𝑘 ∈ 𝐵, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘))} = {𝑘 ∈ ℕ0
∣ hadd(𝑘 ∈ 𝐵, 𝑘 ∈ 𝐴, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘))}) | 
| 4 |  | simpl 482 | . . 3
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → 𝐴 ⊆
ℕ0) | 
| 5 |  | simpr 484 | . . 3
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → 𝐵 ⊆
ℕ0) | 
| 6 |  | eqid 2736 | . . 3
⊢
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 − 1)))) =
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1)))) | 
| 7 | 4, 5, 6 | sadfval 16490 | . 2
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → (𝐴 sadd 𝐵) = {𝑘 ∈ ℕ0 ∣
hadd(𝑘 ∈ 𝐴, 𝑘 ∈ 𝐵, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘))}) | 
| 8 |  | cadcoma 1611 | . . . . . . 7
⊢
(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐) ↔ cadd(𝑚 ∈ 𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐)) | 
| 9 | 8 | a1i 11 | . . . . . 6
⊢ ((𝑐 ∈ 2o ∧
𝑚 ∈
ℕ0) → (cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐) ↔ cadd(𝑚 ∈ 𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐))) | 
| 10 | 9 | ifbid 4548 | . . . . 5
⊢ ((𝑐 ∈ 2o ∧
𝑚 ∈
ℕ0) → if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅) = if(cadd(𝑚 ∈ 𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐), 1o, ∅)) | 
| 11 | 10 | mpoeq3ia 7512 | . . . 4
⊢ (𝑐 ∈ 2o, 𝑚 ∈ ℕ0
↦ if(cadd(𝑚 ∈
𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)) = (𝑐 ∈ 2o, 𝑚 ∈ ℕ0
↦ if(cadd(𝑚 ∈
𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐), 1o, ∅)) | 
| 12 |  | seqeq2 14047 | . . . 4
⊢ ((𝑐 ∈ 2o, 𝑚 ∈ ℕ0
↦ if(cadd(𝑚 ∈
𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)) = (𝑐 ∈ 2o, 𝑚 ∈ ℕ0
↦ if(cadd(𝑚 ∈
𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐), 1o, ∅)) →
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 − 1)))) =
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))) | 
| 13 | 11, 12 | ax-mp 5 | . . 3
⊢
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 − 1)))) =
seq0((𝑐 ∈
2o, 𝑚 ∈
ℕ0 ↦ if(cadd(𝑚 ∈ 𝐵, 𝑚 ∈ 𝐴, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1)))) | 
| 14 | 5, 4, 13 | sadfval 16490 | . 2
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → (𝐵 sadd 𝐴) = {𝑘 ∈ ℕ0 ∣
hadd(𝑘 ∈ 𝐵, 𝑘 ∈ 𝐴, ∅ ∈ (seq0((𝑐 ∈ 2o, 𝑚 ∈ ℕ0 ↦
if(cadd(𝑚 ∈ 𝐴, 𝑚 ∈ 𝐵, ∅ ∈ 𝑐), 1o, ∅)), (𝑛 ∈ ℕ0
↦ if(𝑛 = 0, ∅,
(𝑛 −
1))))‘𝑘))}) | 
| 15 | 3, 7, 14 | 3eqtr4d 2786 | 1
⊢ ((𝐴 ⊆ ℕ0
∧ 𝐵 ⊆
ℕ0) → (𝐴 sadd 𝐵) = (𝐵 sadd 𝐴)) |