Metamath Proof Explorer


Theorem fullresc

Description: The category formed by structure restriction is the same as the category restriction. (Contributed by Mario Carneiro, 5-Jan-2017)

Ref Expression
Hypotheses fullsubc.b ⊢ B = Base C
fullsubc.h ⊢ H = Hom 𝑓 ⁡ C
fullsubc.c ⊢ φ → C ∈ Cat
fullsubc.s ⊢ φ → S ⊆ B
fullsubc.d ⊢ D = C ↾ 𝑠 S
fullsubc.e ⊢ E = C ↾ cat H ↾ S × S
Assertion fullresc ⊢ φ → Hom 𝑓 ⁡ D = Hom 𝑓 ⁡ E ∧ comp 𝑓 ⁡ D = comp 𝑓 ⁡ E

Proof

Step Hyp Ref Expression
1 fullsubc.b ⊢ B = Base C
2 fullsubc.h ⊢ H = Hom 𝑓 ⁡ C
3 fullsubc.c ⊢ φ → C ∈ Cat
4 fullsubc.s ⊢ φ → S ⊆ B
5 fullsubc.d ⊢ D = C ↾ 𝑠 S
6 fullsubc.e ⊢ E = C ↾ cat H ↾ S × S
7 eqid ⊢ Hom ⁡ C = Hom ⁡ C
8 4 adantr ⊢ φ ∧ x ∈ S ∧ y ∈ S → S ⊆ B
9 simprl ⊢ φ ∧ x ∈ S ∧ y ∈ S → x ∈ S
10 8 9 sseldd ⊢ φ ∧ x ∈ S ∧ y ∈ S → x ∈ B
11 simprr ⊢ φ ∧ x ∈ S ∧ y ∈ S → y ∈ S
12 8 11 sseldd ⊢ φ ∧ x ∈ S ∧ y ∈ S → y ∈ B
13 2 1 7 10 12 homfval ⊢ φ ∧ x ∈ S ∧ y ∈ S → x H y = x Hom ⁡ C y
14 9 11 ovresd ⊢ φ ∧ x ∈ S ∧ y ∈ S → x H ↾ S × S y = x H y
15 2 1 homffn ⊢ H Fn B × B
16 xpss12 ⊢ S ⊆ B ∧ S ⊆ B → S × S ⊆ B × B
17 4 4 16 syl2anc ⊢ φ → S × S ⊆ B × B
18 fnssres ⊢ H Fn B × B ∧ S × S ⊆ B × B → H ↾ S × S Fn S × S
19 15 17 18 sylancr ⊢ φ → H ↾ S × S Fn S × S
20 6 1 3 19 4 reschom ⊢ φ → H ↾ S × S = Hom ⁡ E
21 20 oveqdr ⊢ φ ∧ x ∈ S ∧ y ∈ S → x H ↾ S × S y = x Hom ⁡ E y
22 14 21 eqtr3d ⊢ φ ∧ x ∈ S ∧ y ∈ S → x H y = x Hom ⁡ E y
23 5 1 ressbas2 ⊢ S ⊆ B → S = Base D
24 4 23 syl ⊢ φ → S = Base D
25 fvex ⊢ Base D ∈ V
26 24 25 eqeltrdi ⊢ φ → S ∈ V
27 5 7 resshom ⊢ S ∈ V → Hom ⁡ C = Hom ⁡ D
28 26 27 syl ⊢ φ → Hom ⁡ C = Hom ⁡ D
29 28 oveqdr ⊢ φ ∧ x ∈ S ∧ y ∈ S → x Hom ⁡ C y = x Hom ⁡ D y
30 13 22 29 3eqtr3rd ⊢ φ ∧ x ∈ S ∧ y ∈ S → x Hom ⁡ D y = x Hom ⁡ E y
31 30 ralrimivva ⊢ φ → ∀ x ∈ S ∀ y ∈ S x Hom ⁡ D y = x Hom ⁡ E y
32 eqid ⊢ Hom ⁡ D = Hom ⁡ D
33 eqid ⊢ Hom ⁡ E = Hom ⁡ E
34 6 1 3 19 4 rescbas ⊢ φ → S = Base E
35 32 33 24 34 homfeq ⊢ φ → Hom 𝑓 ⁡ D = Hom 𝑓 ⁡ E ↔ ∀ x ∈ S ∀ y ∈ S x Hom ⁡ D y = x Hom ⁡ E y
36 31 35 mpbird ⊢ φ → Hom 𝑓 ⁡ D = Hom 𝑓 ⁡ E
37 eqid ⊢ comp ⁡ C = comp ⁡ C
38 5 37 ressco ⊢ S ∈ V → comp ⁡ C = comp ⁡ D
39 26 38 syl ⊢ φ → comp ⁡ C = comp ⁡ D
40 6 1 3 19 4 37 rescco ⊢ φ → comp ⁡ C = comp ⁡ E
41 39 40 eqtr3d ⊢ φ → comp ⁡ D = comp ⁡ E
42 41 36 comfeqd ⊢ φ → comp 𝑓 ⁡ D = comp 𝑓 ⁡ E
43 36 42 jca ⊢ φ → Hom 𝑓 ⁡ D = Hom 𝑓 ⁡ E ∧ comp 𝑓 ⁡ D = comp 𝑓 ⁡ E