Metamath Proof Explorer


Definition df-fth

Description: Function returning all the faithful functors from a category C to a category D . A faithful functor is a functor in which all the morphism maps G ( X , Y ) between objects X , Y e. C are injections. Definition 3.27(2) in Adamek p. 34. (Contributed by Mario Carneiro, 26-Jan-2017)

Ref Expression
Assertion df-fth
|- Faith = ( c e. Cat , d e. Cat |-> { <. f , g >. | ( f ( c Func d ) g /\ A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y ) ) } )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cfth
 |-  Faith
1 vc
 |-  c
2 ccat
 |-  Cat
3 vd
 |-  d
4 vf
 |-  f
5 vg
 |-  g
6 4 cv
 |-  f
7 1 cv
 |-  c
8 cfunc
 |-  Func
9 3 cv
 |-  d
10 7 9 8 co
 |-  ( c Func d )
11 5 cv
 |-  g
12 6 11 10 wbr
 |-  f ( c Func d ) g
13 vx
 |-  x
14 cbs
 |-  Base
15 7 14 cfv
 |-  ( Base ` c )
16 vy
 |-  y
17 13 cv
 |-  x
18 16 cv
 |-  y
19 17 18 11 co
 |-  ( x g y )
20 19 ccnv
 |-  `' ( x g y )
21 20 wfun
 |-  Fun `' ( x g y )
22 21 16 15 wral
 |-  A. y e. ( Base ` c ) Fun `' ( x g y )
23 22 13 15 wral
 |-  A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y )
24 12 23 wa
 |-  ( f ( c Func d ) g /\ A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y ) )
25 24 4 5 copab
 |-  { <. f , g >. | ( f ( c Func d ) g /\ A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y ) ) }
26 1 3 2 2 25 cmpo
 |-  ( c e. Cat , d e. Cat |-> { <. f , g >. | ( f ( c Func d ) g /\ A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y ) ) } )
27 0 26 wceq
 |-  Faith = ( c e. Cat , d e. Cat |-> { <. f , g >. | ( f ( c Func d ) g /\ A. x e. ( Base ` c ) A. y e. ( Base ` c ) Fun `' ( x g y ) ) } )