Description: Define multiplicative inverse. (Contributed by NM, 21-Sep-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-invr | |- invr = ( r e. _V |-> ( invg ` ( ( mulGrp ` r ) |`s ( Unit ` r ) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cinvr | |- invr |
|
| 1 | vr | |- r |
|
| 2 | cvv | |- _V |
|
| 3 | cminusg | |- invg |
|
| 4 | cmgp | |- mulGrp |
|
| 5 | 1 | cv | |- r |
| 6 | 5 4 | cfv | |- ( mulGrp ` r ) |
| 7 | cress | |- |`s |
|
| 8 | cui | |- Unit |
|
| 9 | 5 8 | cfv | |- ( Unit ` r ) |
| 10 | 6 9 7 | co | |- ( ( mulGrp ` r ) |`s ( Unit ` r ) ) |
| 11 | 10 3 | cfv | |- ( invg ` ( ( mulGrp ` r ) |`s ( Unit ` r ) ) ) |
| 12 | 1 2 11 | cmpt | |- ( r e. _V |-> ( invg ` ( ( mulGrp ` r ) |`s ( Unit ` r ) ) ) ) |
| 13 | 0 12 | wceq | |- invr = ( r e. _V |-> ( invg ` ( ( mulGrp ` r ) |`s ( Unit ` r ) ) ) ) |