Metamath Proof Explorer


Theorem 2arwcat

Description: The condition for a structure with at most one object and at most two morphisms being a category. "2arwcat.2" to "2arwcat.5" are also necessary conditions if X , .0. , and .1. are all sets, due to catlid , catrid , and catcocl . (Contributed by Zhi Wang, 5-Nov-2025)

Ref Expression
Hypotheses 2arwcat.b φ X = Base C
2arwcat.h φ H = Hom C
2arwcat.x φ · ˙ = comp C
2arwcat.1 X H X = 0 ˙ 1 ˙
2arwcat.2 φ 1 ˙ X X · ˙ X 1 ˙ = 1 ˙
2arwcat.3 φ 1 ˙ X X · ˙ X 0 ˙ = 0 ˙
2arwcat.4 φ 0 ˙ X X · ˙ X 1 ˙ = 0 ˙
2arwcat.5 φ 0 ˙ X X · ˙ X 0 ˙ 0 ˙ 1 ˙
Assertion 2arwcat φ C Cat Id C = y X 1 ˙

Proof

Step Hyp Ref Expression
1 2arwcat.b φ X = Base C
2 2arwcat.h φ H = Hom C
3 2arwcat.x φ · ˙ = comp C
4 2arwcat.1 X H X = 0 ˙ 1 ˙
5 2arwcat.2 φ 1 ˙ X X · ˙ X 1 ˙ = 1 ˙
6 2arwcat.3 φ 1 ˙ X X · ˙ X 0 ˙ = 0 ˙
7 2arwcat.4 φ 0 ˙ X X · ˙ X 1 ˙ = 0 ˙
8 2arwcat.5 φ 0 ˙ X X · ˙ X 0 ˙ 0 ˙ 1 ˙
9 ovex 1 ˙ X X · ˙ X 1 ˙ V
10 5 9 eqeltrrdi φ 1 ˙ V
11 prid2g 1 ˙ V 1 ˙ 0 ˙ 1 ˙
12 10 11 syl φ 1 ˙ 0 ˙ 1 ˙
13 12 4 eleqtrrdi φ 1 ˙ X H X
14 df-ov X H X = H X X
15 2 fveq1d φ H X X = Hom C X X
16 14 15 eqtrid φ X H X = Hom C X X
17 13 16 eleqtrd φ 1 ˙ Hom C X X
18 elfv2ex 1 ˙ Hom C X X C V
19 17 18 syl φ C V
20 4 2arwcatlem1 x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x X y X z X w X f x H y g y H z k z H w
21 12 adantr φ y X 1 ˙ 0 ˙ 1 ˙
22 velsn y X y = X
23 id y = X y = X
24 23 23 oveq12d y = X y H y = X H X
25 24 4 eqtrdi y = X y H y = 0 ˙ 1 ˙
26 22 25 sylbi y X y H y = 0 ˙ 1 ˙
27 26 adantl φ y X y H y = 0 ˙ 1 ˙
28 21 27 eleqtrrd φ y X 1 ˙ y H y
29 simprll φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x = X y = X
30 29 simpld φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x = X
31 29 simprd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ y = X
32 simprr1 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ f = 1 ˙
33 5 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X 1 ˙ = 1 ˙
34 6 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X 0 ˙ = 0 ˙
35 30 31 31 32 33 34 2arwcatlem2 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ x y · ˙ y f = f
36 simprlr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ z = X w = X
37 36 simpld φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ z = X
38 simprr2 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g = 0 ˙ g = 1 ˙
39 7 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 0 ˙ X X · ˙ X 1 ˙ = 0 ˙
40 31 31 37 38 33 39 2arwcatlem3 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g y y · ˙ z 1 ˙ = g
41 8 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 0 ˙ X X · ˙ X 0 ˙ 0 ˙ 1 ˙
42 30 31 37 32 33 39 34 41 38 2arwcatlem4 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g x y · ˙ z f 0 ˙ 1 ˙
43 30 37 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x H z = X H X
44 43 4 eqtrdi φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x H z = 0 ˙ 1 ˙
45 42 44 eleqtrrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g x y · ˙ z f x H z
46 6 7 8 2arwcatlem5 φ 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙ = 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙
47 46 ad4antr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙ = 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙
48 simpr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k = 0 ˙
49 simplr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ g = 0 ˙
50 48 49 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k X X · ˙ X g = 0 ˙ X X · ˙ X 0 ˙
51 simpr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ f = 0 ˙
52 51 ad2antrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ f = 0 ˙
53 50 52 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k X X · ˙ X g X X · ˙ X f = 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙
54 49 52 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ g X X · ˙ X f = 0 ˙ X X · ˙ X 0 ˙
55 48 54 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k X X · ˙ X g X X · ˙ X f = 0 ˙ X X · ˙ X 0 ˙ X X · ˙ X 0 ˙
56 47 53 55 3eqtr4d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
57 eqidd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ X = X
58 30 31 opeq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x y = X X
59 58 37 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x y · ˙ z = X X · ˙ X
60 59 oveqd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g x y · ˙ z f = g X X · ˙ X f
61 60 42 eqeltrrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g X X · ˙ X f 0 ˙ 1 ˙
62 ovex g X X · ˙ X f V
63 62 elpr g X X · ˙ X f 0 ˙ 1 ˙ g X X · ˙ X f = 0 ˙ g X X · ˙ X f = 1 ˙
64 61 63 sylib φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g X X · ˙ X f = 0 ˙ g X X · ˙ X f = 1 ˙
65 57 57 57 64 33 34 2arwcatlem2 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X g X X · ˙ X f = g X X · ˙ X f
66 65 ad3antrrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X g X X · ˙ X f = g X X · ˙ X f
67 simpr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k = 1 ˙
68 67 oveq1d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k X X · ˙ X g X X · ˙ X f = 1 ˙ X X · ˙ X g X X · ˙ X f
69 67 oveq1d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k X X · ˙ X g = 1 ˙ X X · ˙ X g
70 57 57 57 38 33 34 2arwcatlem2 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X g = g
71 70 ad3antrrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X g = g
72 69 71 eqtrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k X X · ˙ X g = g
73 72 oveq1d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k X X · ˙ X g X X · ˙ X f = g X X · ˙ X f
74 66 68 73 3eqtr4rd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
75 simprr3 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k = 0 ˙ k = 1 ˙
76 75 ad2antrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k = 0 ˙ k = 1 ˙
77 56 74 76 mpjaodan φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
78 simpr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ g = 1 ˙
79 78 oveq2d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X g = k X X · ˙ X 1 ˙
80 57 57 57 75 33 39 2arwcatlem3 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k X X · ˙ X 1 ˙ = k
81 80 ad2antrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X 1 ˙ = k
82 79 81 eqtrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X g = k
83 82 oveq1d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X f
84 78 oveq1d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ g X X · ˙ X f = 1 ˙ X X · ˙ X f
85 57 57 57 32 33 34 2arwcatlem2 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ 1 ˙ X X · ˙ X f = f
86 85 ad2antrr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ 1 ˙ X X · ˙ X f = f
87 84 86 eqtrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ g X X · ˙ X f = f
88 87 oveq2d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X f
89 83 88 eqtr4d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
90 38 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ g = 0 ˙ g = 1 ˙
91 77 89 90 mpjaodan φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 0 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
92 57 57 57 38 33 39 34 41 75 2arwcatlem4 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k X X · ˙ X g 0 ˙ 1 ˙
93 ovex k X X · ˙ X g V
94 93 elpr k X X · ˙ X g 0 ˙ 1 ˙ k X X · ˙ X g = 0 ˙ k X X · ˙ X g = 1 ˙
95 92 94 sylib φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k X X · ˙ X g = 0 ˙ k X X · ˙ X g = 1 ˙
96 57 57 57 95 33 39 2arwcatlem3 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k X X · ˙ X g X X · ˙ X 1 ˙ = k X X · ˙ X g
97 96 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ k X X · ˙ X g X X · ˙ X 1 ˙ = k X X · ˙ X g
98 simpr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ f = 1 ˙
99 98 oveq2d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X 1 ˙
100 98 oveq2d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ g X X · ˙ X f = g X X · ˙ X 1 ˙
101 57 57 57 38 33 39 2arwcatlem3 φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ g X X · ˙ X 1 ˙ = g
102 101 adantr φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ g X X · ˙ X 1 ˙ = g
103 100 102 eqtrd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ g X X · ˙ X f = g
104 103 oveq2d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g
105 97 99 104 3eqtr4d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
106 91 105 32 mpjaodan φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k X X · ˙ X g X X · ˙ X f = k X X · ˙ X g X X · ˙ X f
107 36 simprd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ w = X
108 58 107 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x y · ˙ w = X X · ˙ X
109 31 37 opeq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ y z = X X
110 109 107 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ y z · ˙ w = X X · ˙ X
111 110 oveqd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k y z · ˙ w g = k X X · ˙ X g
112 eqidd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ f = f
113 108 111 112 oveq123d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k y z · ˙ w g x y · ˙ w f = k X X · ˙ X g X X · ˙ X f
114 30 37 opeq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x z = X X
115 114 107 oveq12d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ x z · ˙ w = X X · ˙ X
116 eqidd φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k = k
117 115 116 60 oveq123d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k x z · ˙ w g x y · ˙ z f = k X X · ˙ X g X X · ˙ X f
118 106 113 117 3eqtr4d φ x = X y = X z = X w = X f = 0 ˙ f = 1 ˙ g = 0 ˙ g = 1 ˙ k = 0 ˙ k = 1 ˙ k y z · ˙ w g x y · ˙ w f = k x z · ˙ w g x y · ˙ z f
119 1 2 3 19 20 28 35 40 45 118 iscatd2 φ C Cat Id C = y X 1 ˙