Description: Define the symmetric difference of two classes. Alternate definitions are dfsymdif2 , dfsymdif3 and dfsymdif4 . (Contributed by Scott Fenton, 31-Mar-2012)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-symdif | |- ( A /_\ B ) = ( ( A \ B ) u. ( B \ A ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cA | |- A | |
| 1 | cB | |- B | |
| 2 | 0 1 | csymdif | |- ( A /_\ B ) | 
| 3 | 0 1 | cdif | |- ( A \ B ) | 
| 4 | 1 0 | cdif | |- ( B \ A ) | 
| 5 | 3 4 | cun | |- ( ( A \ B ) u. ( B \ A ) ) | 
| 6 | 2 5 | wceq | |- ( A /_\ B ) = ( ( A \ B ) u. ( B \ A ) ) |