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=BaseC
fullsubc.h H=Hom𝑓C
fullsubc.c φCCat
fullsubc.s φSB
fullsubc.d D=C𝑠S
fullsubc.e E=CcatHS×S
Assertion fullresc φHom𝑓D=Hom𝑓Ecomp𝑓D=comp𝑓E

Proof

Step Hyp Ref Expression
1 fullsubc.b B=BaseC
2 fullsubc.h H=Hom𝑓C
3 fullsubc.c φCCat
4 fullsubc.s φSB
5 fullsubc.d D=C𝑠S
6 fullsubc.e E=CcatHS×S
7 eqid HomC=HomC
8 4 adantr φxSySSB
9 simprl φxSySxS
10 8 9 sseldd φxSySxB
11 simprr φxSySyS
12 8 11 sseldd φxSySyB
13 2 1 7 10 12 homfval φxSySxHy=xHomCy
14 9 11 ovresd φxSySxHS×Sy=xHy
15 2 1 homffn HFnB×B
16 xpss12 SBSBS×SB×B
17 4 4 16 syl2anc φS×SB×B
18 fnssres HFnB×BS×SB×BHS×SFnS×S
19 15 17 18 sylancr φHS×SFnS×S
20 6 1 3 19 4 reschom φHS×S=HomE
21 20 oveqdr φxSySxHS×Sy=xHomEy
22 14 21 eqtr3d φxSySxHy=xHomEy
23 5 1 ressbas2 SBS=BaseD
24 4 23 syl φS=BaseD
25 fvex BaseDV
26 24 25 eqeltrdi φSV
27 5 7 resshom SVHomC=HomD
28 26 27 syl φHomC=HomD
29 28 oveqdr φxSySxHomCy=xHomDy
30 13 22 29 3eqtr3rd φxSySxHomDy=xHomEy
31 30 ralrimivva φxSySxHomDy=xHomEy
32 eqid HomD=HomD
33 eqid HomE=HomE
34 6 1 3 19 4 rescbas φS=BaseE
35 32 33 24 34 homfeq φHom𝑓D=Hom𝑓ExSySxHomDy=xHomEy
36 31 35 mpbird φHom𝑓D=Hom𝑓E
37 eqid compC=compC
38 5 37 ressco SVcompC=compD
39 26 38 syl φcompC=compD
40 6 1 3 19 4 37 rescco φcompC=compE
41 39 40 eqtr3d φcompD=compE
42 41 36 comfeqd φcomp𝑓D=comp𝑓E
43 36 42 jca φHom𝑓D=Hom𝑓Ecomp𝑓D=comp𝑓E