Theorem discsubc 49727

Description: A discrete category, whose only morphisms are the identity morphisms, is a subcategory. (Contributed by Zhi Wang, 1-Nov-2025.)

Hypotheses

Ref	Expression
discsubc.j	⊢ 𝐽 = (𝑥 ∈ 𝑆, 𝑦 ∈ 𝑆 ↦ if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅))
discsubc.b	⊢ 𝐵 = (Base‘𝐶)
discsubc.i	⊢ 𝐼 = (Id‘𝐶)
discsubc.s	⊢ (𝜑 → 𝑆 ⊆ 𝐵)
discsubc.c	⊢ (𝜑 → 𝐶 ∈ Cat)

Assertion

Ref	Expression
discsubc	⊢ (𝜑 → 𝐽 ∈ (Subcat‘𝐶))

Distinct variable groups:   𝑥,𝑆,𝑦   𝑥,𝐼,𝑦

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐵(𝑥,𝑦)   𝐶(𝑥,𝑦)   𝐽(𝑥,𝑦)

Proof of Theorem discsubc

Dummy variables 𝑎 𝑏 𝑐 𝑓 𝑔 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		discsubc.s	. . 3 ⊢ (𝜑 → 𝑆 ⊆ 𝐵)
2		eqeq12 2786	. . . . . . . 8 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑏) → (𝑥 = 𝑦 ↔ 𝑎 = 𝑏))
3		simpl 487	. . . . . . . . . 10 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑏) → 𝑥 = 𝑎)
4	3	fveq2d 6886	. . . . . . . . 9 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑏) → (𝐼‘𝑥) = (𝐼‘𝑎))
5	4	sneqd 4606	. . . . . . . 8 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑏) → {(𝐼‘𝑥)} = {(𝐼‘𝑎)})
6	2, 5	ifbieq1d 4517	. . . . . . 7 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑏) → if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅) = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅))
7		discsubc.j	. . . . . . 7 ⊢ 𝐽 = (𝑥 ∈ 𝑆, 𝑦 ∈ 𝑆 ↦ if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅))
8		snex 5411	. . . . . . . 8 ⊢ {(𝐼‘𝑎)} ∈ V
9		0ex 5272	. . . . . . . 8 ⊢ ∅ ∈ V
10	8, 9	ifex 4543	. . . . . . 7 ⊢ if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ∈ V
11	6, 7, 10	ovmpoa 7566	. . . . . 6 ⊢ ((𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆) → (𝑎𝐽𝑏) = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅))
12	11	adantl 486	. . . . 5 ⊢ ((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) → (𝑎𝐽𝑏) = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅))
13		sseq1 3970	. . . . . 6 ⊢ ({(𝐼‘𝑎)} = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) → ({(𝐼‘𝑎)} ⊆ (𝑎(Homf ‘𝐶)𝑏) ↔ if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ⊆ (𝑎(Homf ‘𝐶)𝑏)))
14		sseq1 3970	. . . . . 6 ⊢ (∅ = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) → (∅ ⊆ (𝑎(Homf ‘𝐶)𝑏) ↔ if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ⊆ (𝑎(Homf ‘𝐶)𝑏)))
15		discsubc.b	. . . . . . . . 9 ⊢ 𝐵 = (Base‘𝐶)
16		eqid 2769	. . . . . . . . 9 ⊢ (Hom ‘𝐶) = (Hom ‘𝐶)
17		discsubc.i	. . . . . . . . 9 ⊢ 𝐼 = (Id‘𝐶)
18		discsubc.c	. . . . . . . . . 10 ⊢ (𝜑 → 𝐶 ∈ Cat)
19	18	ad2antrr 738	. . . . . . . . 9 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → 𝐶 ∈ Cat)
20	1	ad2antrr 738	. . . . . . . . . 10 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → 𝑆 ⊆ 𝐵)
21		simplrl 788	. . . . . . . . . 10 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → 𝑎 ∈ 𝑆)
22	20, 21	sseldd 3946	. . . . . . . . 9 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → 𝑎 ∈ 𝐵)
23	15, 16, 17, 19, 22	catidcl 17738	. . . . . . . 8 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → (𝐼‘𝑎) ∈ (𝑎(Hom ‘𝐶)𝑎))
24		eqid 2769	. . . . . . . . . 10 ⊢ (Homf ‘𝐶) = (Homf ‘𝐶)
25	24, 15, 16, 22, 22	homfval 17748	. . . . . . . . 9 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → (𝑎(Homf ‘𝐶)𝑎) = (𝑎(Hom ‘𝐶)𝑎))
26		simpr 489	. . . . . . . . . 10 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → 𝑎 = 𝑏)
27	26	oveq2d 7427	. . . . . . . . 9 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → (𝑎(Homf ‘𝐶)𝑎) = (𝑎(Homf ‘𝐶)𝑏))
28	25, 27	eqtr3d 2806	. . . . . . . 8 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → (𝑎(Hom ‘𝐶)𝑎) = (𝑎(Homf ‘𝐶)𝑏))
29	23, 28	eleqtrd 2871	. . . . . . 7 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → (𝐼‘𝑎) ∈ (𝑎(Homf ‘𝐶)𝑏))
30	29	snssd 4757	. . . . . 6 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ 𝑎 = 𝑏) → {(𝐼‘𝑎)} ⊆ (𝑎(Homf ‘𝐶)𝑏))
31		0ss 4364	. . . . . . 7 ⊢ ∅ ⊆ (𝑎(Homf ‘𝐶)𝑏)
32	31	a1i 11	. . . . . 6 ⊢ (((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) ∧ ¬ 𝑎 = 𝑏) → ∅ ⊆ (𝑎(Homf ‘𝐶)𝑏))
33	13, 14, 30, 32	ifbothda 4531	. . . . 5 ⊢ ((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) → if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ⊆ (𝑎(Homf ‘𝐶)𝑏))
34	12, 33	eqsstrd 3979	. . . 4 ⊢ ((𝜑 ∧ (𝑎 ∈ 𝑆 ∧ 𝑏 ∈ 𝑆)) → (𝑎𝐽𝑏) ⊆ (𝑎(Homf ‘𝐶)𝑏))
35	34	ralrimivva 3214	. . 3 ⊢ (𝜑 → ∀𝑎 ∈ 𝑆 ∀𝑏 ∈ 𝑆 (𝑎𝐽𝑏) ⊆ (𝑎(Homf ‘𝐶)𝑏))
36	7	discsubclem 49726	. . . . 5 ⊢ 𝐽 Fn (𝑆 × 𝑆)
37	36	a1i 11	. . . 4 ⊢ (𝜑 → 𝐽 Fn (𝑆 × 𝑆))
38	24, 15	homffn 17749	. . . . 5 ⊢ (Homf ‘𝐶) Fn (𝐵 × 𝐵)
39	38	a1i 11	. . . 4 ⊢ (𝜑 → (Homf ‘𝐶) Fn (𝐵 × 𝐵))
40	15	fvexi 6896	. . . . 5 ⊢ 𝐵 ∈ V
41	40	a1i 11	. . . 4 ⊢ (𝜑 → 𝐵 ∈ V)
42	37, 39, 41	isssc 17877	. . 3 ⊢ (𝜑 → (𝐽 ⊆cat (Homf ‘𝐶) ↔ (𝑆 ⊆ 𝐵 ∧ ∀𝑎 ∈ 𝑆 ∀𝑏 ∈ 𝑆 (𝑎𝐽𝑏) ⊆ (𝑎(Homf ‘𝐶)𝑏))))
43	1, 35, 42	mpbir2and 725	. 2 ⊢ (𝜑 → 𝐽 ⊆cat (Homf ‘𝐶))
44		fvex 6895	. . . . . 6 ⊢ (𝐼‘𝑎) ∈ V
45	44	snid 4633	. . . . 5 ⊢ (𝐼‘𝑎) ∈ {(𝐼‘𝑎)}
46		simpr 489	. . . . . 6 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → 𝑎 ∈ 𝑆)
47		equtr2 2054	. . . . . . . . 9 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → 𝑥 = 𝑦)
48	47	iftrued 4500	. . . . . . . 8 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅) = {(𝐼‘𝑥)})
49		simpl 487	. . . . . . . . . 10 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → 𝑥 = 𝑎)
50	49	fveq2d 6886	. . . . . . . . 9 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → (𝐼‘𝑥) = (𝐼‘𝑎))
51	50	sneqd 4606	. . . . . . . 8 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → {(𝐼‘𝑥)} = {(𝐼‘𝑎)})
52	48, 51	eqtrd 2804	. . . . . . 7 ⊢ ((𝑥 = 𝑎 ∧ 𝑦 = 𝑎) → if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅) = {(𝐼‘𝑎)})
53	52, 7, 8	ovmpoa 7566	. . . . . 6 ⊢ ((𝑎 ∈ 𝑆 ∧ 𝑎 ∈ 𝑆) → (𝑎𝐽𝑎) = {(𝐼‘𝑎)})
54	46, 46, 53	syl2anc 595	. . . . 5 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → (𝑎𝐽𝑎) = {(𝐼‘𝑎)})
55	45, 54	eleqtrrid 2876	. . . 4 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → (𝐼‘𝑎) ∈ (𝑎𝐽𝑎))
56	45	a1i 11	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝐼‘𝑎) ∈ {(𝐼‘𝑎)})
57		simprl 782	. . . . . . . . . . . . . . 15 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑓 ∈ (𝑎𝐽𝑏))
58	46	ad2antrr 738	. . . . . . . . . . . . . . . 16 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑎 ∈ 𝑆)
59		simplrl 788	. . . . . . . . . . . . . . . 16 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑏 ∈ 𝑆)
60	58, 59, 11	syl2anc 595	. . . . . . . . . . . . . . 15 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑎𝐽𝑏) = if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅))
61	57, 60	eleqtrd 2871	. . . . . . . . . . . . . 14 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑓 ∈ if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅))
62	61	ne0d 4303	. . . . . . . . . . . . 13 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ≠ ∅)
63		iffalse 4501	. . . . . . . . . . . . . 14 ⊢ (¬ 𝑎 = 𝑏 → if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) = ∅)
64	63	necon1ai 2991	. . . . . . . . . . . . 13 ⊢ (if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) ≠ ∅ → 𝑎 = 𝑏)
65	62, 64	syl 18	. . . . . . . . . . . 12 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑎 = 𝑏)
66	65	opeq2d 4849	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → ⟨𝑎, 𝑎⟩ = ⟨𝑎, 𝑏⟩)
67		simprr 784	. . . . . . . . . . . . . . 15 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑔 ∈ (𝑏𝐽𝑐))
68		eqeq12 2786	. . . . . . . . . . . . . . . . . 18 ⊢ ((𝑥 = 𝑏 ∧ 𝑦 = 𝑐) → (𝑥 = 𝑦 ↔ 𝑏 = 𝑐))
69		simpl 487	. . . . . . . . . . . . . . . . . . . 20 ⊢ ((𝑥 = 𝑏 ∧ 𝑦 = 𝑐) → 𝑥 = 𝑏)
70	69	fveq2d 6886	. . . . . . . . . . . . . . . . . . 19 ⊢ ((𝑥 = 𝑏 ∧ 𝑦 = 𝑐) → (𝐼‘𝑥) = (𝐼‘𝑏))
71	70	sneqd 4606	. . . . . . . . . . . . . . . . . 18 ⊢ ((𝑥 = 𝑏 ∧ 𝑦 = 𝑐) → {(𝐼‘𝑥)} = {(𝐼‘𝑏)})
72	68, 71	ifbieq1d 4517	. . . . . . . . . . . . . . . . 17 ⊢ ((𝑥 = 𝑏 ∧ 𝑦 = 𝑐) → if(𝑥 = 𝑦, {(𝐼‘𝑥)}, ∅) = if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅))
73		snex 5411	. . . . . . . . . . . . . . . . . 18 ⊢ {(𝐼‘𝑏)} ∈ V
74	73, 9	ifex 4543	. . . . . . . . . . . . . . . . 17 ⊢ if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅) ∈ V
75	72, 7, 74	ovmpoa 7566	. . . . . . . . . . . . . . . 16 ⊢ ((𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆) → (𝑏𝐽𝑐) = if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅))
76	75	ad2antlr 739	. . . . . . . . . . . . . . 15 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑏𝐽𝑐) = if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅))
77	67, 76	eleqtrd 2871	. . . . . . . . . . . . . 14 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑔 ∈ if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅))
78	77	ne0d 4303	. . . . . . . . . . . . 13 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅) ≠ ∅)
79		iffalse 4501	. . . . . . . . . . . . . 14 ⊢ (¬ 𝑏 = 𝑐 → if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅) = ∅)
80	79	necon1ai 2991	. . . . . . . . . . . . 13 ⊢ (if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅) ≠ ∅ → 𝑏 = 𝑐)
81	78, 80	syl 18	. . . . . . . . . . . 12 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑏 = 𝑐)
82	65, 81	eqtrd 2804	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑎 = 𝑐)
83	66, 82	oveq12d 7429	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (⟨𝑎, 𝑎⟩(comp‘𝐶)𝑎) = (⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐))
84	83	eqcomd 2775	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐) = (⟨𝑎, 𝑎⟩(comp‘𝐶)𝑎))
85	81	iftrued 4500	. . . . . . . . . . . 12 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → if(𝑏 = 𝑐, {(𝐼‘𝑏)}, ∅) = {(𝐼‘𝑏)})
86	77, 85	eleqtrd 2871	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑔 ∈ {(𝐼‘𝑏)})
87	86	elsnd 4612	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑔 = (𝐼‘𝑏))
88	65	fveq2d 6886	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝐼‘𝑎) = (𝐼‘𝑏))
89	87, 88	eqtr4d 2807	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑔 = (𝐼‘𝑎))
90	65	iftrued 4500	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → if(𝑎 = 𝑏, {(𝐼‘𝑎)}, ∅) = {(𝐼‘𝑎)})
91	61, 90	eleqtrd 2871	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑓 ∈ {(𝐼‘𝑎)})
92	91	elsnd 4612	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑓 = (𝐼‘𝑎))
93	84, 89, 92	oveq123d 7432	. . . . . . . 8 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) = ((𝐼‘𝑎)(⟨𝑎, 𝑎⟩(comp‘𝐶)𝑎)(𝐼‘𝑎)))
94	18	ad3antrrr 742	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝐶 ∈ Cat)
95	1	ad3antrrr 742	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑆 ⊆ 𝐵)
96	95, 58	sseldd 3946	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → 𝑎 ∈ 𝐵)
97		eqid 2769	. . . . . . . . 9 ⊢ (comp‘𝐶) = (comp‘𝐶)
98	15, 16, 17, 94, 96	catidcl 17738	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝐼‘𝑎) ∈ (𝑎(Hom ‘𝐶)𝑎))
99	15, 16, 17, 94, 96, 97, 96, 98	catlid 17739	. . . . . . . 8 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → ((𝐼‘𝑎)(⟨𝑎, 𝑎⟩(comp‘𝐶)𝑎)(𝐼‘𝑎)) = (𝐼‘𝑎))
100	93, 99	eqtrd 2804	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) = (𝐼‘𝑎))
101	82	oveq2d 7427	. . . . . . . 8 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑎𝐽𝑎) = (𝑎𝐽𝑐))
102	58, 58, 53	syl2anc 595	. . . . . . . 8 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑎𝐽𝑎) = {(𝐼‘𝑎)})
103	101, 102	eqtr3d 2806	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑎𝐽𝑐) = {(𝐼‘𝑎)})
104	56, 100, 103	3eltr4d 2884	. . . . . 6 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐽𝑏) ∧ 𝑔 ∈ (𝑏𝐽𝑐))) → (𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐))
105	104	ralrimivva 3214	. . . . 5 ⊢ (((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) → ∀𝑓 ∈ (𝑎𝐽𝑏)∀𝑔 ∈ (𝑏𝐽𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐))
106	105	ralrimivva 3214	. . . 4 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐽𝑏)∀𝑔 ∈ (𝑏𝐽𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐))
107	55, 106	jca 520	. . 3 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → ((𝐼‘𝑎) ∈ (𝑎𝐽𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐽𝑏)∀𝑔 ∈ (𝑏𝐽𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐)))
108	107	ralrimiva 3163	. 2 ⊢ (𝜑 → ∀𝑎 ∈ 𝑆 ((𝐼‘𝑎) ∈ (𝑎𝐽𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐽𝑏)∀𝑔 ∈ (𝑏𝐽𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐)))
109	24, 17, 97, 18, 37	issubc2 17893	. 2 ⊢ (𝜑 → (𝐽 ∈ (Subcat‘𝐶) ↔ (𝐽 ⊆cat (Homf ‘𝐶) ∧ ∀𝑎 ∈ 𝑆 ((𝐼‘𝑎) ∈ (𝑎𝐽𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐽𝑏)∀𝑔 ∈ (𝑏𝐽𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐶)𝑐)𝑓) ∈ (𝑎𝐽𝑐)))))
110	43, 108, 109	mpbir2and 725	1 ⊢ (𝜑 → 𝐽 ∈ (Subcat‘𝐶))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 400   = wceq 1567   ∈ wcel 2149   ≠ wne 2964  ∀wral 3085  Vcvv 3463   ⊆ wss 3913  ∅c0 4294  ifcif 4492  {csn 4594  ⟨cop 4600   class class class wbr 5113   × cxp 5660   Fn wfn 6532  ‘cfv 6537  (class class class)co 7411   ∈ cmpo 7413  Basecbs 17269  Hom chom 17321  compcco 17322  Catccat 17720  Idccid 17721  Hom_f chomf 17722   ⊆_cat cssc 17864  Subcatcsubc 17866

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-10 2182  ax-11 2198  ax-12 2219  ax-ext 2741  ax-rep 5242  ax-sep 5261  ax-nul 5271  ax-pow 5337  ax-pr 5405  ax-un 7733

This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1570  df-fal 1580  df-ex 1807  df-nf 1811  df-sb 2098  df-mo 2573  df-eu 2603  df-clab 2748  df-cleq 2761  df-clel 2844  df-nfc 2918  df-ne 2965  df-ral 3086  df-rex 3096  df-rmo 3376  df-reu 3377  df-rab 3424  df-v 3465  df-sbc 3754  df-csb 3862  df-dif 3916  df-un 3918  df-in 3920  df-ss 3930  df-nul 4295  df-if 4493  df-pw 4569  df-sn 4595  df-pr 4597  df-op 4601  df-uni 4877  df-iun 4962  df-br 5114  df-opab 5178  df-mpt 5197  df-id 5557  df-xp 5668  df-rel 5669  df-cnv 5670  df-co 5671  df-dm 5672  df-rn 5673  df-res 5674  df-ima 5675  df-iota 6493  df-fun 6539  df-fn 6540  df-f 6541  df-f1 6542  df-fo 6543  df-f1o 6544  df-fv 6545  df-riota 7368  df-ov 7414  df-oprab 7415  df-mpo 7416  df-1st 7986  df-2nd 7987  df-pm 8827  df-ixp 8896  df-cat 17724  df-cid 17725  df-homf 17726  df-ssc 17867  df-subc 17869

This theorem is referenced by:  iinfconstbaslem  49728