Metamath Proof Explorer


Theorem xpcpropd

Description: If two categories have the same set of objects, morphisms, and compositions, then they have the same product category. (Contributed by Mario Carneiro, 17-Jan-2017)

Ref Expression
Hypotheses xpcpropd.1 ⊢ φ → Hom 𝑓 ⁡ A = Hom 𝑓 ⁡ B
xpcpropd.2 ⊢ φ → comp 𝑓 ⁡ A = comp 𝑓 ⁡ B
xpcpropd.3 ⊢ φ → Hom 𝑓 ⁡ C = Hom 𝑓 ⁡ D
xpcpropd.4 ⊢ φ → comp 𝑓 ⁡ C = comp 𝑓 ⁡ D
xpcpropd.a ⊢ φ → A ∈ V
xpcpropd.b ⊢ φ → B ∈ V
xpcpropd.c ⊢ φ → C ∈ V
xpcpropd.d ⊢ φ → D ∈ V
Assertion xpcpropd ⊢ φ → A × c C = B × c D

Proof

Step Hyp Ref Expression
1 xpcpropd.1 ⊢ φ → Hom 𝑓 ⁡ A = Hom 𝑓 ⁡ B
2 xpcpropd.2 ⊢ φ → comp 𝑓 ⁡ A = comp 𝑓 ⁡ B
3 xpcpropd.3 ⊢ φ → Hom 𝑓 ⁡ C = Hom 𝑓 ⁡ D
4 xpcpropd.4 ⊢ φ → comp 𝑓 ⁡ C = comp 𝑓 ⁡ D
5 xpcpropd.a ⊢ φ → A ∈ V
6 xpcpropd.b ⊢ φ → B ∈ V
7 xpcpropd.c ⊢ φ → C ∈ V
8 xpcpropd.d ⊢ φ → D ∈ V
9 eqid ⊢ A × c C = A × c C
10 eqid ⊢ Base A = Base A
11 eqid ⊢ Base C = Base C
12 eqid ⊢ Hom ⁡ A = Hom ⁡ A
13 eqid ⊢ Hom ⁡ C = Hom ⁡ C
14 eqid ⊢ comp ⁡ A = comp ⁡ A
15 eqid ⊢ comp ⁡ C = comp ⁡ C
16 eqidd ⊢ φ → Base A × Base C = Base A × Base C
17 9 10 11 xpcbas ⊢ Base A × Base C = Base A × c C
18 eqid ⊢ Hom ⁡ A × c C = Hom ⁡ A × c C
19 9 17 12 13 18 xpchomfval ⊢ Hom ⁡ A × c C = u ∈ Base A × Base C , v ∈ Base A × Base C ⟼ 1 st ⁡ u Hom ⁡ A 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ C 2 nd ⁡ v
20 19 a1i ⊢ φ → Hom ⁡ A × c C = u ∈ Base A × Base C , v ∈ Base A × Base C ⟼ 1 st ⁡ u Hom ⁡ A 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ C 2 nd ⁡ v
21 eqidd ⊢ φ → x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f
22 9 10 11 12 13 14 15 5 7 16 20 21 xpcval ⊢ φ → A × c C = Base ndx Base A × Base C Hom ⁡ ndx Hom ⁡ A × c C comp ⁡ ndx x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f
23 eqid ⊢ B × c D = B × c D
24 eqid ⊢ Base B = Base B
25 eqid ⊢ Base D = Base D
26 eqid ⊢ Hom ⁡ B = Hom ⁡ B
27 eqid ⊢ Hom ⁡ D = Hom ⁡ D
28 eqid ⊢ comp ⁡ B = comp ⁡ B
29 eqid ⊢ comp ⁡ D = comp ⁡ D
30 1 homfeqbas ⊢ φ → Base A = Base B
31 3 homfeqbas ⊢ φ → Base C = Base D
32 30 31 xpeq12d ⊢ φ → Base A × Base C = Base B × Base D
33 1 3ad2ant1 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → Hom 𝑓 ⁡ A = Hom 𝑓 ⁡ B
34 xp1st ⊢ u ∈ Base A × Base C → 1 st ⁡ u ∈ Base A
35 34 3ad2ant2 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 1 st ⁡ u ∈ Base A
36 xp1st ⊢ v ∈ Base A × Base C → 1 st ⁡ v ∈ Base A
37 36 3ad2ant3 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 1 st ⁡ v ∈ Base A
38 10 12 26 33 35 37 homfeqval ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 1 st ⁡ u Hom ⁡ A 1 st ⁡ v = 1 st ⁡ u Hom ⁡ B 1 st ⁡ v
39 3 3ad2ant1 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → Hom 𝑓 ⁡ C = Hom 𝑓 ⁡ D
40 xp2nd ⊢ u ∈ Base A × Base C → 2 nd ⁡ u ∈ Base C
41 40 3ad2ant2 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 2 nd ⁡ u ∈ Base C
42 xp2nd ⊢ v ∈ Base A × Base C → 2 nd ⁡ v ∈ Base C
43 42 3ad2ant3 ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 2 nd ⁡ v ∈ Base C
44 11 13 27 39 41 43 homfeqval ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 2 nd ⁡ u Hom ⁡ C 2 nd ⁡ v = 2 nd ⁡ u Hom ⁡ D 2 nd ⁡ v
45 38 44 xpeq12d ⊢ φ ∧ u ∈ Base A × Base C ∧ v ∈ Base A × Base C → 1 st ⁡ u Hom ⁡ A 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ C 2 nd ⁡ v = 1 st ⁡ u Hom ⁡ B 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ D 2 nd ⁡ v
46 45 mpoeq3dva ⊢ φ → u ∈ Base A × Base C , v ∈ Base A × Base C ⟼ 1 st ⁡ u Hom ⁡ A 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ C 2 nd ⁡ v = u ∈ Base A × Base C , v ∈ Base A × Base C ⟼ 1 st ⁡ u Hom ⁡ B 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ D 2 nd ⁡ v
47 19 46 eqtrid ⊢ φ → Hom ⁡ A × c C = u ∈ Base A × Base C , v ∈ Base A × Base C ⟼ 1 st ⁡ u Hom ⁡ B 1 st ⁡ v × 2 nd ⁡ u Hom ⁡ D 2 nd ⁡ v
48 1 ad4antr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → Hom 𝑓 ⁡ A = Hom 𝑓 ⁡ B
49 2 ad4antr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → comp 𝑓 ⁡ A = comp 𝑓 ⁡ B
50 simp-4r ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → x ∈ Base A × Base C × Base A × Base C
51 xp1st ⊢ x ∈ Base A × Base C × Base A × Base C → 1 st ⁡ x ∈ Base A × Base C
52 50 51 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ x ∈ Base A × Base C
53 xp1st ⊢ 1 st ⁡ x ∈ Base A × Base C → 1 st ⁡ 1 st ⁡ x ∈ Base A
54 52 53 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ 1 st ⁡ x ∈ Base A
55 xp2nd ⊢ x ∈ Base A × Base C × Base A × Base C → 2 nd ⁡ x ∈ Base A × Base C
56 50 55 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ x ∈ Base A × Base C
57 xp1st ⊢ 2 nd ⁡ x ∈ Base A × Base C → 1 st ⁡ 2 nd ⁡ x ∈ Base A
58 56 57 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ 2 nd ⁡ x ∈ Base A
59 simpllr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → y ∈ Base A × Base C
60 xp1st ⊢ y ∈ Base A × Base C → 1 st ⁡ y ∈ Base A
61 59 60 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ y ∈ Base A
62 simpr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → f ∈ Hom ⁡ A × c C ⁡ x
63 1st2nd2 ⊢ x ∈ Base A × Base C × Base A × Base C → x = 1 st ⁡ x 2 nd ⁡ x
64 50 63 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → x = 1 st ⁡ x 2 nd ⁡ x
65 64 fveq2d ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → Hom ⁡ A × c C ⁡ x = Hom ⁡ A × c C ⁡ 1 st ⁡ x 2 nd ⁡ x
66 df-ov ⊢ 1 st ⁡ x Hom ⁡ A × c C 2 nd ⁡ x = Hom ⁡ A × c C ⁡ 1 st ⁡ x 2 nd ⁡ x
67 65 66 eqtr4di ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → Hom ⁡ A × c C ⁡ x = 1 st ⁡ x Hom ⁡ A × c C 2 nd ⁡ x
68 9 17 12 13 18 52 56 xpchom ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ x Hom ⁡ A × c C 2 nd ⁡ x = 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x × 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x
69 67 68 eqtrd ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → Hom ⁡ A × c C ⁡ x = 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x × 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x
70 62 69 eleqtrd ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → f ∈ 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x × 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x
71 xp1st ⊢ f ∈ 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x × 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x → 1 st ⁡ f ∈ 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x
72 70 71 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ f ∈ 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x
73 simplr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → g ∈ 2 nd ⁡ x Hom ⁡ A × c C y
74 9 17 12 13 18 56 59 xpchom ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ x Hom ⁡ A × c C y = 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y × 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y
75 73 74 eleqtrd ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → g ∈ 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y × 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y
76 xp1st ⊢ g ∈ 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y × 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y → 1 st ⁡ g ∈ 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y
77 75 76 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ g ∈ 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y
78 10 12 14 28 48 49 54 58 61 72 77 comfeqval ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f = 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f
79 3 ad4antr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → Hom 𝑓 ⁡ C = Hom 𝑓 ⁡ D
80 4 ad4antr ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → comp 𝑓 ⁡ C = comp 𝑓 ⁡ D
81 xp2nd ⊢ 1 st ⁡ x ∈ Base A × Base C → 2 nd ⁡ 1 st ⁡ x ∈ Base C
82 52 81 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ 1 st ⁡ x ∈ Base C
83 xp2nd ⊢ 2 nd ⁡ x ∈ Base A × Base C → 2 nd ⁡ 2 nd ⁡ x ∈ Base C
84 56 83 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ 2 nd ⁡ x ∈ Base C
85 xp2nd ⊢ y ∈ Base A × Base C → 2 nd ⁡ y ∈ Base C
86 59 85 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ y ∈ Base C
87 xp2nd ⊢ f ∈ 1 st ⁡ 1 st ⁡ x Hom ⁡ A 1 st ⁡ 2 nd ⁡ x × 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x → 2 nd ⁡ f ∈ 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x
88 70 87 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ f ∈ 2 nd ⁡ 1 st ⁡ x Hom ⁡ C 2 nd ⁡ 2 nd ⁡ x
89 xp2nd ⊢ g ∈ 1 st ⁡ 2 nd ⁡ x Hom ⁡ A 1 st ⁡ y × 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y → 2 nd ⁡ g ∈ 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y
90 75 89 syl ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ g ∈ 2 nd ⁡ 2 nd ⁡ x Hom ⁡ C 2 nd ⁡ y
91 11 13 15 29 79 80 82 84 86 88 90 comfeqval ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
92 78 91 opeq12d ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
93 92 3impa ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C ∧ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y ∧ f ∈ Hom ⁡ A × c C ⁡ x → 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
94 93 mpoeq3dva ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C → g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
95 94 3impa ⊢ φ ∧ x ∈ Base A × Base C × Base A × Base C ∧ y ∈ Base A × Base C → g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
96 95 mpoeq3dva ⊢ φ → x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f = x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ B 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ D 2 nd ⁡ y 2 nd ⁡ f
97 23 24 25 26 27 28 29 6 8 32 47 96 xpcval ⊢ φ → B × c D = Base ndx Base A × Base C Hom ⁡ ndx Hom ⁡ A × c C comp ⁡ ndx x ∈ Base A × Base C × Base A × Base C , y ∈ Base A × Base C ⟼ g ∈ 2 nd ⁡ x Hom ⁡ A × c C y , f ∈ Hom ⁡ A × c C ⁡ x ⟼ 1 st ⁡ g 1 st ⁡ 1 st ⁡ x 1 st ⁡ 2 nd ⁡ x comp ⁡ A 1 st ⁡ y 1 st ⁡ f 2 nd ⁡ g 2 nd ⁡ 1 st ⁡ x 2 nd ⁡ 2 nd ⁡ x comp ⁡ C 2 nd ⁡ y 2 nd ⁡ f
98 22 97 eqtr4d ⊢ φ → A × c C = B × c D