Description: Define a quotient ring (or quotient group), which is a special case of an image structure df-imas where the image function is x |-> [ x ] e . (Contributed by Mario Carneiro, 23-Feb-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-qus | |- /s = ( r e. _V , e e. _V |-> ( ( x e. ( Base ` r ) |-> [ x ] e ) "s r ) )  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cqus | |- /s  | 
						|
| 1 | vr | |- r  | 
						|
| 2 | cvv | |- _V  | 
						|
| 3 | ve | |- e  | 
						|
| 4 | vx | |- x  | 
						|
| 5 | cbs | |- Base  | 
						|
| 6 | 1 | cv | |- r  | 
						
| 7 | 6 5 | cfv | |- ( Base ` r )  | 
						
| 8 | 4 | cv | |- x  | 
						
| 9 | 3 | cv | |- e  | 
						
| 10 | 8 9 | cec | |- [ x ] e  | 
						
| 11 | 4 7 10 | cmpt | |- ( x e. ( Base ` r ) |-> [ x ] e )  | 
						
| 12 | cimas | |- "s  | 
						|
| 13 | 11 6 12 | co | |- ( ( x e. ( Base ` r ) |-> [ x ] e ) "s r )  | 
						
| 14 | 1 3 2 2 13 | cmpo | |- ( r e. _V , e e. _V |-> ( ( x e. ( Base ` r ) |-> [ x ] e ) "s r ) )  | 
						
| 15 | 0 14 | wceq | |- /s = ( r e. _V , e e. _V |-> ( ( x e. ( Base ` r ) |-> [ x ] e ) "s r ) )  |