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 ( 𝐴 △ 𝐵 ) = ( ( 𝐴 ∖ 𝐵 ) ∪ ( 𝐵 ∖ 𝐴 ) )

Detailed syntax breakdown

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 ) ∪ ( 𝐵 ∖ 𝐴 ) )
6 2 5 wceq ⊢ ( 𝐴 △ 𝐵 ) = ( ( 𝐴 ∖ 𝐵 ) ∪ ( 𝐵 ∖ 𝐴 ) )