| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | peano2 7912 | . . . . 5
⊢ (𝐵 ∈ ω → suc 𝐵 ∈
ω) | 
| 2 |  | nnon 7893 | . . . . 5
⊢ (suc
𝐵 ∈ ω → suc
𝐵 ∈
On) | 
| 3 | 1, 2 | syl 17 | . . . 4
⊢ (𝐵 ∈ ω → suc 𝐵 ∈ On) | 
| 4 |  | omv 8550 | . . . 4
⊢ ((𝐴 ∈ On ∧ suc 𝐵 ∈ On) → (𝐴 ·o suc 𝐵) = (rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅)‘suc 𝐵)) | 
| 5 | 3, 4 | sylan2 593 | . . 3
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → (𝐴 ·o suc 𝐵) = (rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅)‘suc 𝐵)) | 
| 6 | 1 | adantl 481 | . . . 4
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → suc
𝐵 ∈
ω) | 
| 7 | 6 | fvresd 6926 | . . 3
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) →
((rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅) ↾
ω)‘suc 𝐵) =
(rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅)‘suc 𝐵)) | 
| 8 | 5, 7 | eqtr4d 2780 | . 2
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → (𝐴 ·o suc 𝐵) = ((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘suc
𝐵)) | 
| 9 |  | ovex 7464 | . . . . 5
⊢ (𝐴 ·o 𝐵) ∈ V | 
| 10 |  | oveq1 7438 | . . . . . 6
⊢ (𝑥 = (𝐴 ·o 𝐵) → (𝑥 +o 𝐴) = ((𝐴 ·o 𝐵) +o 𝐴)) | 
| 11 |  | eqid 2737 | . . . . . 6
⊢ (𝑥 ∈ V ↦ (𝑥 +o 𝐴)) = (𝑥 ∈ V ↦ (𝑥 +o 𝐴)) | 
| 12 |  | ovex 7464 | . . . . . 6
⊢ ((𝐴 ·o 𝐵) +o 𝐴) ∈ V | 
| 13 | 10, 11, 12 | fvmpt 7016 | . . . . 5
⊢ ((𝐴 ·o 𝐵) ∈ V → ((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘(𝐴 ·o 𝐵)) = ((𝐴 ·o 𝐵) +o 𝐴)) | 
| 14 | 9, 13 | ax-mp 5 | . . . 4
⊢ ((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘(𝐴 ·o 𝐵)) = ((𝐴 ·o 𝐵) +o 𝐴) | 
| 15 |  | nnon 7893 | . . . . . . 7
⊢ (𝐵 ∈ ω → 𝐵 ∈ On) | 
| 16 |  | omv 8550 | . . . . . . 7
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On) → (𝐴 ·o 𝐵) = (rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅)‘𝐵)) | 
| 17 | 15, 16 | sylan2 593 | . . . . . 6
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → (𝐴 ·o 𝐵) = (rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅)‘𝐵)) | 
| 18 |  | fvres 6925 | . . . . . . 7
⊢ (𝐵 ∈ ω →
((rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅) ↾
ω)‘𝐵) =
(rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅)‘𝐵)) | 
| 19 | 18 | adantl 481 | . . . . . 6
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) →
((rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅) ↾
ω)‘𝐵) =
(rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅)‘𝐵)) | 
| 20 | 17, 19 | eqtr4d 2780 | . . . . 5
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → (𝐴 ·o 𝐵) = ((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘𝐵)) | 
| 21 | 20 | fveq2d 6910 | . . . 4
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → ((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘(𝐴 ·o 𝐵)) = ((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘𝐵))) | 
| 22 | 14, 21 | eqtr3id 2791 | . . 3
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → ((𝐴 ·o 𝐵) +o 𝐴) = ((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘𝐵))) | 
| 23 |  | frsuc 8477 | . . . 4
⊢ (𝐵 ∈ ω →
((rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅) ↾
ω)‘suc 𝐵) =
((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘𝐵))) | 
| 24 | 23 | adantl 481 | . . 3
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) →
((rec((𝑥 ∈ V ↦
(𝑥 +o 𝐴)), ∅) ↾
ω)‘suc 𝐵) =
((𝑥 ∈ V ↦ (𝑥 +o 𝐴))‘((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘𝐵))) | 
| 25 | 22, 24 | eqtr4d 2780 | . 2
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → ((𝐴 ·o 𝐵) +o 𝐴) = ((rec((𝑥 ∈ V ↦ (𝑥 +o 𝐴)), ∅) ↾ ω)‘suc
𝐵)) | 
| 26 | 8, 25 | eqtr4d 2780 | 1
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ ω) → (𝐴 ·o suc 𝐵) = ((𝐴 ·o 𝐵) +o 𝐴)) |