Theorem symdif2 3520

Description: Two ways to express symmetric difference. (Contributed by NM, 17-Aug-2004.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)

Assertion

Ref	Expression
symdif2	|- ((A \ B) u. (B \ A)) = {x | -. (x e. A <-> x e. B)}

Distinct variable groups:   x,A   x,B

Proof of Theorem symdif2

Step	Hyp	Ref	Expression
1		eldif 3221	. . . 4 |- (x e. (A \ B) <-> (x e. A /\ -. x e. B))
2		eldif 3221	. . . 4 |- (x e. (B \ A) <-> (x e. B /\ -. x e. A))
3	1, 2	orbi12i 507	. . 3 |- ((x e. (A \ B) \/ x e. (B \ A)) <-> ((x e. A /\ -. x e. B) \/ (x e. B /\ -. x e. A)))
4		elun 3220	. . 3 |- (x e. ((A \ B) u. (B \ A)) <-> (x e. (A \ B) \/ x e. (B \ A)))
5		xor 861	. . 3 |- (-. (x e. A <-> x e. B) <-> ((x e. A /\ -. x e. B) \/ (x e. B /\ -. x e. A)))
6	3, 4, 5	3bitr4i 268	. 2 |- (x e. ((A \ B) u. (B \ A)) <-> -. (x e. A <-> x e. B))
7	6	abbi2i 2464	1 |- ((A \ B) u. (B \ A)) = {x | -. (x e. A <-> x e. B)}

Syntax hints:  -. wn 3   <-> wb 176   \/ wo 357   /\ wa 358   = wceq 1642   e. wcel 1710  {cab 2339   \ cdif 3206   u. cun 3207

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-un 3214  df-dif 3215

This theorem is referenced by: (None)