Description: Define class of all division rings. A division ring is a ring in which the set of units is exactly the nonzero elements of the ring. (Contributed by NM, 18-Oct-2012)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-drng | |- DivRing = { r e. Ring | ( Unit ` r ) = ( ( Base ` r ) \ { ( 0g ` r ) } ) } | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cdr | |- DivRing | |
| 1 | vr | |- r | |
| 2 | crg | |- Ring | |
| 3 | cui | |- Unit | |
| 4 | 1 | cv | |- r | 
| 5 | 4 3 | cfv | |- ( Unit ` r ) | 
| 6 | cbs | |- Base | |
| 7 | 4 6 | cfv | |- ( Base ` r ) | 
| 8 | c0g | |- 0g | |
| 9 | 4 8 | cfv | |- ( 0g ` r ) | 
| 10 | 9 | csn |  |-  { ( 0g ` r ) } | 
| 11 | 7 10 | cdif |  |-  ( ( Base ` r ) \ { ( 0g ` r ) } ) | 
| 12 | 5 11 | wceq |  |-  ( Unit ` r ) = ( ( Base ` r ) \ { ( 0g ` r ) } ) | 
| 13 | 12 1 2 | crab |  |-  { r e. Ring | ( Unit ` r ) = ( ( Base ` r ) \ { ( 0g ` r ) } ) } | 
| 14 | 0 13 | wceq |  |-  DivRing = { r e. Ring | ( Unit ` r ) = ( ( Base ` r ) \ { ( 0g ` r ) } ) } |