Description: Define a function that maps a group operation to the group's inverse function. (Contributed by NM, 26-Oct-2006) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | df-ginv | |- inv = ( g e. GrpOp |-> ( x e. ran g |-> ( iota_ z e. ran g ( z g x ) = ( GId ` g ) ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | cgn | |- inv |
|
1 | vg | |- g |
|
2 | cgr | |- GrpOp |
|
3 | vx | |- x |
|
4 | 1 | cv | |- g |
5 | 4 | crn | |- ran g |
6 | vz | |- z |
|
7 | 6 | cv | |- z |
8 | 3 | cv | |- x |
9 | 7 8 4 | co | |- ( z g x ) |
10 | cgi | |- GId |
|
11 | 4 10 | cfv | |- ( GId ` g ) |
12 | 9 11 | wceq | |- ( z g x ) = ( GId ` g ) |
13 | 12 6 5 | crio | |- ( iota_ z e. ran g ( z g x ) = ( GId ` g ) ) |
14 | 3 5 13 | cmpt | |- ( x e. ran g |-> ( iota_ z e. ran g ( z g x ) = ( GId ` g ) ) ) |
15 | 1 2 14 | cmpt | |- ( g e. GrpOp |-> ( x e. ran g |-> ( iota_ z e. ran g ( z g x ) = ( GId ` g ) ) ) ) |
16 | 0 15 | wceq | |- inv = ( g e. GrpOp |-> ( x e. ran g |-> ( iota_ z e. ran g ( z g x ) = ( GId ` g ) ) ) ) |