Metamath Proof Explorer


Definition df-symdif

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 AB=ABBA

Detailed syntax breakdown

Step Hyp Ref Expression
0 cA classA
1 cB classB
2 0 1 csymdif classAB
3 0 1 cdif classAB
4 1 0 cdif classBA
5 3 4 cun classABBA
6 2 5 wceq wffAB=ABBA