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 ) ) ) ) |