| Step | Hyp | Ref | Expression | 
						
							| 0 |  | cdomn |  |-  Domn | 
						
							| 1 |  | vr |  |-  r | 
						
							| 2 |  | cnzr |  |-  NzRing | 
						
							| 3 |  | cbs |  |-  Base | 
						
							| 4 | 1 | cv |  |-  r | 
						
							| 5 | 4 3 | cfv |  |-  ( Base ` r ) | 
						
							| 6 |  | vb |  |-  b | 
						
							| 7 |  | c0g |  |-  0g | 
						
							| 8 | 4 7 | cfv |  |-  ( 0g ` r ) | 
						
							| 9 |  | vz |  |-  z | 
						
							| 10 |  | vx |  |-  x | 
						
							| 11 | 6 | cv |  |-  b | 
						
							| 12 |  | vy |  |-  y | 
						
							| 13 | 10 | cv |  |-  x | 
						
							| 14 |  | cmulr |  |-  .r | 
						
							| 15 | 4 14 | cfv |  |-  ( .r ` r ) | 
						
							| 16 | 12 | cv |  |-  y | 
						
							| 17 | 13 16 15 | co |  |-  ( x ( .r ` r ) y ) | 
						
							| 18 | 9 | cv |  |-  z | 
						
							| 19 | 17 18 | wceq |  |-  ( x ( .r ` r ) y ) = z | 
						
							| 20 | 13 18 | wceq |  |-  x = z | 
						
							| 21 | 16 18 | wceq |  |-  y = z | 
						
							| 22 | 20 21 | wo |  |-  ( x = z \/ y = z ) | 
						
							| 23 | 19 22 | wi |  |-  ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) | 
						
							| 24 | 23 12 11 | wral |  |-  A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) | 
						
							| 25 | 24 10 11 | wral |  |-  A. x e. b A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) | 
						
							| 26 | 25 9 8 | wsbc |  |-  [. ( 0g ` r ) / z ]. A. x e. b A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) | 
						
							| 27 | 26 6 5 | wsbc |  |-  [. ( Base ` r ) / b ]. [. ( 0g ` r ) / z ]. A. x e. b A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) | 
						
							| 28 | 27 1 2 | crab |  |-  { r e. NzRing | [. ( Base ` r ) / b ]. [. ( 0g ` r ) / z ]. A. x e. b A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) } | 
						
							| 29 | 0 28 | wceq |  |-  Domn = { r e. NzRing | [. ( Base ` r ) / b ]. [. ( 0g ` r ) / z ]. A. x e. b A. y e. b ( ( x ( .r ` r ) y ) = z -> ( x = z \/ y = z ) ) } |