| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | resundir 6012 | . . . . . 6
⊢
((((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ∪ ((V ∖ Fin) × {+∞}))
↾ Fin) = ((((rec((𝑥
∈ V ↦ (𝑥 + 1)),
0) ↾ ω) ∘ card) ↾ Fin) ∪ (((V ∖ Fin) ×
{+∞}) ↾ Fin)) | 
| 2 |  | eqid 2737 | . . . . . . . . . 10
⊢
(rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) = (rec((𝑥
∈ V ↦ (𝑥 + 1)),
0) ↾ ω) | 
| 3 |  | eqid 2737 | . . . . . . . . . 10
⊢
((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) = ((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘
card) | 
| 4 | 2, 3 | hashkf 14371 | . . . . . . . . 9
⊢
((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card):Fin⟶ℕ0 | 
| 5 |  | ffn 6736 | . . . . . . . . 9
⊢
(((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card):Fin⟶ℕ0 →
((rec((𝑥 ∈ V ↦
(𝑥 + 1)), 0) ↾
ω) ∘ card) Fn Fin) | 
| 6 |  | fnresdm 6687 | . . . . . . . . 9
⊢
(((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) Fn Fin → (((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘ card)
↾ Fin) = ((rec((𝑥
∈ V ↦ (𝑥 + 1)),
0) ↾ ω) ∘ card)) | 
| 7 | 4, 5, 6 | mp2b 10 | . . . . . . . 8
⊢
(((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ↾ Fin) = ((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘
card) | 
| 8 |  | disjdifr 4473 | . . . . . . . . 9
⊢ ((V
∖ Fin) ∩ Fin) = ∅ | 
| 9 |  | pnfex 11314 | . . . . . . . . . . 11
⊢ +∞
∈ V | 
| 10 | 9 | fconst 6794 | . . . . . . . . . 10
⊢ ((V
∖ Fin) × {+∞}):(V ∖
Fin)⟶{+∞} | 
| 11 |  | ffn 6736 | . . . . . . . . . 10
⊢ (((V
∖ Fin) × {+∞}):(V ∖ Fin)⟶{+∞} → ((V
∖ Fin) × {+∞}) Fn (V ∖ Fin)) | 
| 12 |  | fnresdisj 6688 | . . . . . . . . . 10
⊢ (((V
∖ Fin) × {+∞}) Fn (V ∖ Fin) → (((V ∖ Fin)
∩ Fin) = ∅ ↔ (((V ∖ Fin) × {+∞}) ↾ Fin)
= ∅)) | 
| 13 | 10, 11, 12 | mp2b 10 | . . . . . . . . 9
⊢ (((V
∖ Fin) ∩ Fin) = ∅ ↔ (((V ∖ Fin) × {+∞})
↾ Fin) = ∅) | 
| 14 | 8, 13 | mpbi 230 | . . . . . . . 8
⊢ (((V
∖ Fin) × {+∞}) ↾ Fin) = ∅ | 
| 15 | 7, 14 | uneq12i 4166 | . . . . . . 7
⊢
((((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ↾ Fin) ∪ (((V ∖ Fin) ×
{+∞}) ↾ Fin)) = (((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘ card)
∪ ∅) | 
| 16 |  | un0 4394 | . . . . . . 7
⊢
(((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ∪ ∅) = ((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘
card) | 
| 17 | 15, 16 | eqtri 2765 | . . . . . 6
⊢
((((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ↾ Fin) ∪ (((V ∖ Fin) ×
{+∞}) ↾ Fin)) = ((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) ∘
card) | 
| 18 | 1, 17 | eqtri 2765 | . . . . 5
⊢
((((rec((𝑥 ∈ V
↦ (𝑥 + 1)), 0)
↾ ω) ∘ card) ∪ ((V ∖ Fin) × {+∞}))
↾ Fin) = ((rec((𝑥
∈ V ↦ (𝑥 + 1)),
0) ↾ ω) ∘ card) | 
| 19 |  | df-hash 14370 | . . . . . 6
⊢ ♯ =
(((rec((𝑥 ∈ V ↦
(𝑥 + 1)), 0) ↾
ω) ∘ card) ∪ ((V ∖ Fin) ×
{+∞})) | 
| 20 | 19 | reseq1i 5993 | . . . . 5
⊢ (♯
↾ Fin) = ((((rec((𝑥
∈ V ↦ (𝑥 + 1)),
0) ↾ ω) ∘ card) ∪ ((V ∖ Fin) × {+∞}))
↾ Fin) | 
| 21 |  | hashgval.1 | . . . . . 6
⊢ 𝐺 = (rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω) | 
| 22 | 21 | coeq1i 5870 | . . . . 5
⊢ (𝐺 ∘ card) = ((rec((𝑥 ∈ V ↦ (𝑥 + 1)), 0) ↾ ω)
∘ card) | 
| 23 | 18, 20, 22 | 3eqtr4i 2775 | . . . 4
⊢ (♯
↾ Fin) = (𝐺 ∘
card) | 
| 24 | 23 | fveq1i 6907 | . . 3
⊢ ((♯
↾ Fin)‘𝐴) =
((𝐺 ∘
card)‘𝐴) | 
| 25 |  | cardf2 9983 | . . . . 5
⊢
card:{𝑥 ∣
∃𝑦 ∈ On 𝑦 ≈ 𝑥}⟶On | 
| 26 |  | ffun 6739 | . . . . 5
⊢
(card:{𝑥 ∣
∃𝑦 ∈ On 𝑦 ≈ 𝑥}⟶On → Fun card) | 
| 27 | 25, 26 | ax-mp 5 | . . . 4
⊢ Fun
card | 
| 28 |  | finnum 9988 | . . . 4
⊢ (𝐴 ∈ Fin → 𝐴 ∈ dom
card) | 
| 29 |  | fvco 7007 | . . . 4
⊢ ((Fun
card ∧ 𝐴 ∈ dom
card) → ((𝐺 ∘
card)‘𝐴) = (𝐺‘(card‘𝐴))) | 
| 30 | 27, 28, 29 | sylancr 587 | . . 3
⊢ (𝐴 ∈ Fin → ((𝐺 ∘ card)‘𝐴) = (𝐺‘(card‘𝐴))) | 
| 31 | 24, 30 | eqtrid 2789 | . 2
⊢ (𝐴 ∈ Fin → ((♯
↾ Fin)‘𝐴) =
(𝐺‘(card‘𝐴))) | 
| 32 |  | fvres 6925 | . 2
⊢ (𝐴 ∈ Fin → ((♯
↾ Fin)‘𝐴) =
(♯‘𝐴)) | 
| 33 | 31, 32 | eqtr3d 2779 | 1
⊢ (𝐴 ∈ Fin → (𝐺‘(card‘𝐴)) = (♯‘𝐴)) |