| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | 2ndfval.p | . 2
⊢ 𝑄 = (𝐶 2ndF 𝐷) | 
| 2 |  | 1stfval.c | . . 3
⊢ (𝜑 → 𝐶 ∈ Cat) | 
| 3 |  | 1stfval.d | . . 3
⊢ (𝜑 → 𝐷 ∈ Cat) | 
| 4 |  | fvex 6918 | . . . . . . 7
⊢
(Base‘𝑐)
∈ V | 
| 5 |  | fvex 6918 | . . . . . . 7
⊢
(Base‘𝑑)
∈ V | 
| 6 | 4, 5 | xpex 7774 | . . . . . 6
⊢
((Base‘𝑐)
× (Base‘𝑑))
∈ V | 
| 7 | 6 | a1i 11 | . . . . 5
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → ((Base‘𝑐) × (Base‘𝑑)) ∈ V) | 
| 8 |  | simpl 482 | . . . . . . . 8
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → 𝑐 = 𝐶) | 
| 9 | 8 | fveq2d 6909 | . . . . . . 7
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → (Base‘𝑐) = (Base‘𝐶)) | 
| 10 |  | simpr 484 | . . . . . . . 8
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → 𝑑 = 𝐷) | 
| 11 | 10 | fveq2d 6909 | . . . . . . 7
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → (Base‘𝑑) = (Base‘𝐷)) | 
| 12 | 9, 11 | xpeq12d 5715 | . . . . . 6
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → ((Base‘𝑐) × (Base‘𝑑)) = ((Base‘𝐶) × (Base‘𝐷))) | 
| 13 |  | 1stfval.t | . . . . . . . 8
⊢ 𝑇 = (𝐶 ×c 𝐷) | 
| 14 |  | eqid 2736 | . . . . . . . 8
⊢
(Base‘𝐶) =
(Base‘𝐶) | 
| 15 |  | eqid 2736 | . . . . . . . 8
⊢
(Base‘𝐷) =
(Base‘𝐷) | 
| 16 | 13, 14, 15 | xpcbas 18224 | . . . . . . 7
⊢
((Base‘𝐶)
× (Base‘𝐷)) =
(Base‘𝑇) | 
| 17 |  | 1stfval.b | . . . . . . 7
⊢ 𝐵 = (Base‘𝑇) | 
| 18 | 16, 17 | eqtr4i 2767 | . . . . . 6
⊢
((Base‘𝐶)
× (Base‘𝐷)) =
𝐵 | 
| 19 | 12, 18 | eqtrdi 2792 | . . . . 5
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → ((Base‘𝑐) × (Base‘𝑑)) = 𝐵) | 
| 20 |  | simpr 484 | . . . . . . 7
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → 𝑏 = 𝐵) | 
| 21 | 20 | reseq2d 5996 | . . . . . 6
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (2nd ↾ 𝑏) = (2nd ↾
𝐵)) | 
| 22 |  | simpll 766 | . . . . . . . . . . . . 13
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → 𝑐 = 𝐶) | 
| 23 |  | simplr 768 | . . . . . . . . . . . . 13
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → 𝑑 = 𝐷) | 
| 24 | 22, 23 | oveq12d 7450 | . . . . . . . . . . . 12
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (𝑐 ×c 𝑑) = (𝐶 ×c 𝐷)) | 
| 25 | 24, 13 | eqtr4di 2794 | . . . . . . . . . . 11
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (𝑐 ×c 𝑑) = 𝑇) | 
| 26 | 25 | fveq2d 6909 | . . . . . . . . . 10
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (Hom ‘(𝑐 ×c 𝑑)) = (Hom ‘𝑇)) | 
| 27 |  | 1stfval.h | . . . . . . . . . 10
⊢ 𝐻 = (Hom ‘𝑇) | 
| 28 | 26, 27 | eqtr4di 2794 | . . . . . . . . 9
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (Hom ‘(𝑐 ×c 𝑑)) = 𝐻) | 
| 29 | 28 | oveqd 7449 | . . . . . . . 8
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦) = (𝑥𝐻𝑦)) | 
| 30 | 29 | reseq2d 5996 | . . . . . . 7
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (2nd ↾ (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦)) = (2nd ↾ (𝑥𝐻𝑦))) | 
| 31 | 20, 20, 30 | mpoeq123dv 7509 | . . . . . 6
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → (𝑥 ∈ 𝑏, 𝑦 ∈ 𝑏 ↦ (2nd ↾ (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦))) = (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))) | 
| 32 | 21, 31 | opeq12d 4880 | . . . . 5
⊢ (((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) ∧ 𝑏 = 𝐵) → 〈(2nd ↾ 𝑏), (𝑥 ∈ 𝑏, 𝑦 ∈ 𝑏 ↦ (2nd ↾ (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦)))〉 = 〈(2nd ↾
𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉) | 
| 33 | 7, 19, 32 | csbied2 3935 | . . . 4
⊢ ((𝑐 = 𝐶 ∧ 𝑑 = 𝐷) → ⦋((Base‘𝑐) × (Base‘𝑑)) / 𝑏⦌〈(2nd ↾
𝑏), (𝑥 ∈ 𝑏, 𝑦 ∈ 𝑏 ↦ (2nd ↾ (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦)))〉 = 〈(2nd ↾
𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉) | 
| 34 |  | df-2ndf 18220 | . . . 4
⊢ 
2ndF = (𝑐 ∈ Cat, 𝑑 ∈ Cat ↦
⦋((Base‘𝑐) × (Base‘𝑑)) / 𝑏⦌〈(2nd ↾
𝑏), (𝑥 ∈ 𝑏, 𝑦 ∈ 𝑏 ↦ (2nd ↾ (𝑥(Hom ‘(𝑐 ×c 𝑑))𝑦)))〉) | 
| 35 |  | opex 5468 | . . . 4
⊢
〈(2nd ↾ 𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉 ∈ V | 
| 36 | 33, 34, 35 | ovmpoa 7589 | . . 3
⊢ ((𝐶 ∈ Cat ∧ 𝐷 ∈ Cat) → (𝐶
2ndF 𝐷) = 〈(2nd ↾ 𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉) | 
| 37 | 2, 3, 36 | syl2anc 584 | . 2
⊢ (𝜑 → (𝐶 2ndF 𝐷) = 〈(2nd
↾ 𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉) | 
| 38 | 1, 37 | eqtrid 2788 | 1
⊢ (𝜑 → 𝑄 = 〈(2nd ↾ 𝐵), (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (2nd ↾ (𝑥𝐻𝑦)))〉) |