Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
The difference, union, and intersection of two classes
The symmetric difference of two classes
df-symdif
Metamath Proof Explorer
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 ) )