Proof of Theorem bnj92
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | bnj92.1 | . . 3
⊢ (𝜓 ↔ ∀𝑖 ∈ ω (suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 2 | 1 | sbcbii 3845 | . 2
⊢
([𝑍 / 𝑛]𝜓 ↔ [𝑍 / 𝑛]∀𝑖 ∈ ω (suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 3 |  | bnj92.2 | . . 3
⊢ 𝑍 ∈ V | 
| 4 | 3 | bnj538 34755 | . 2
⊢
([𝑍 / 𝑛]∀𝑖 ∈ ω (suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ ∀𝑖 ∈ ω [𝑍 / 𝑛](suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 5 |  | sbcimg 3836 | . . . . 5
⊢ (𝑍 ∈ V → ([𝑍 / 𝑛](suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ ([𝑍 / 𝑛]suc 𝑖 ∈ 𝑛 → [𝑍 / 𝑛](𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)))) | 
| 6 | 3, 5 | ax-mp 5 | . . . 4
⊢
([𝑍 / 𝑛](suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ ([𝑍 / 𝑛]suc 𝑖 ∈ 𝑛 → [𝑍 / 𝑛](𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 7 |  | sbcel2gv 3856 | . . . . . 6
⊢ (𝑍 ∈ V → ([𝑍 / 𝑛]suc 𝑖 ∈ 𝑛 ↔ suc 𝑖 ∈ 𝑍)) | 
| 8 | 3, 7 | ax-mp 5 | . . . . 5
⊢
([𝑍 / 𝑛]suc 𝑖 ∈ 𝑛 ↔ suc 𝑖 ∈ 𝑍) | 
| 9 | 3 | bnj525 34753 | . . . . 5
⊢
([𝑍 / 𝑛](𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅) ↔ (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) | 
| 10 | 8, 9 | imbi12i 350 | . . . 4
⊢
(([𝑍 / 𝑛]suc 𝑖 ∈ 𝑛 → [𝑍 / 𝑛](𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ (suc 𝑖 ∈ 𝑍 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 11 | 6, 10 | bitri 275 | . . 3
⊢
([𝑍 / 𝑛](suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ (suc 𝑖 ∈ 𝑍 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 12 | 11 | ralbii 3092 | . 2
⊢
(∀𝑖 ∈
ω [𝑍 / 𝑛](suc 𝑖 ∈ 𝑛 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅)) ↔ ∀𝑖 ∈ ω (suc 𝑖 ∈ 𝑍 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) | 
| 13 | 2, 4, 12 | 3bitri 297 | 1
⊢
([𝑍 / 𝑛]𝜓 ↔ ∀𝑖 ∈ ω (suc 𝑖 ∈ 𝑍 → (𝑓‘suc 𝑖) = ∪ 𝑦 ∈ (𝑓‘𝑖) pred(𝑦, 𝐴, 𝑅))) |