Metamath Proof Explorer


Definition df-fae

Description: Define a builder for an 'almost everywhere' relation between functions, from relations between function values. In this definition, the range of f and g is enforced in order to ensure the resulting relation is a set. (Contributed by Thierry Arnoux, 22-Oct-2017)

Ref Expression
Assertion df-fae
|- ~ae = ( r e. _V , m e. U. ran measures |-> { <. f , g >. | ( ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) ) /\ { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m ) } )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cfae
 |-  ~ae
1 vr
 |-  r
2 cvv
 |-  _V
3 vm
 |-  m
4 cmeas
 |-  measures
5 4 crn
 |-  ran measures
6 5 cuni
 |-  U. ran measures
7 vf
 |-  f
8 vg
 |-  g
9 7 cv
 |-  f
10 1 cv
 |-  r
11 10 cdm
 |-  dom r
12 cmap
 |-  ^m
13 3 cv
 |-  m
14 13 cdm
 |-  dom m
15 14 cuni
 |-  U. dom m
16 11 15 12 co
 |-  ( dom r ^m U. dom m )
17 9 16 wcel
 |-  f e. ( dom r ^m U. dom m )
18 8 cv
 |-  g
19 18 16 wcel
 |-  g e. ( dom r ^m U. dom m )
20 17 19 wa
 |-  ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) )
21 vx
 |-  x
22 21 cv
 |-  x
23 22 9 cfv
 |-  ( f ` x )
24 22 18 cfv
 |-  ( g ` x )
25 23 24 10 wbr
 |-  ( f ` x ) r ( g ` x )
26 25 21 15 crab
 |-  { x e. U. dom m | ( f ` x ) r ( g ` x ) }
27 cae
 |-  ae
28 26 13 27 wbr
 |-  { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m
29 20 28 wa
 |-  ( ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) ) /\ { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m )
30 29 7 8 copab
 |-  { <. f , g >. | ( ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) ) /\ { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m ) }
31 1 3 2 6 30 cmpo
 |-  ( r e. _V , m e. U. ran measures |-> { <. f , g >. | ( ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) ) /\ { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m ) } )
32 0 31 wceq
 |-  ~ae = ( r e. _V , m e. U. ran measures |-> { <. f , g >. | ( ( f e. ( dom r ^m U. dom m ) /\ g e. ( dom r ^m U. dom m ) ) /\ { x e. U. dom m | ( f ` x ) r ( g ` x ) } ae m ) } )