Theorem difin 3446

Description: Difference with intersection. Theorem 33 of [Suppes] p. 29. (Contributed by NM, 31-Mar-1998.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)

Assertion

Ref	Expression
difin	|- ( A \ ( A i^i B ) ) = ( A \ B )

Proof of Theorem difin

Dummy variable x is distinct from all other variables.

Step	Hyp	Ref	Expression
1		ax-in2 620	. . . . . . . 8 |- ( -. ( x e. A /\ x e. B ) -> ( ( x e. A /\ x e. B ) -> F. ) )
2	1	expd 258	. . . . . . 7 |- ( -. ( x e. A /\ x e. B ) -> ( x e. A -> ( x e. B -> F. ) ) )
3		dfnot 1416	. . . . . . 7 |- ( -. x e. B <-> ( x e. B -> F. ) )
4	2, 3	imbitrrdi 162	. . . . . 6 |- ( -. ( x e. A /\ x e. B ) -> ( x e. A -> -. x e. B ) )
5	4	com12 30	. . . . 5 |- ( x e. A -> ( -. ( x e. A /\ x e. B ) -> -. x e. B ) )
6	5	imdistani 445	. . . 4 |- ( ( x e. A /\ -. ( x e. A /\ x e. B ) ) -> ( x e. A /\ -. x e. B ) )
7		simpr 110	. . . . . 6 |- ( ( x e. A /\ x e. B ) -> x e. B )
8	7	con3i 637	. . . . 5 |- ( -. x e. B -> -. ( x e. A /\ x e. B ) )
9	8	anim2i 342	. . . 4 |- ( ( x e. A /\ -. x e. B ) -> ( x e. A /\ -. ( x e. A /\ x e. B ) ) )
10	6, 9	impbii 126	. . 3 |- ( ( x e. A /\ -. ( x e. A /\ x e. B ) ) <-> ( x e. A /\ -. x e. B ) )
11		eldif 3210	. . . 4 |- ( x e. ( A \ ( A i^i B ) ) <-> ( x e. A /\ -. x e. ( A i^i B ) ) )
12		elin 3392	. . . . . 6 |- ( x e. ( A i^i B ) <-> ( x e. A /\ x e. B ) )
13	12	notbii 674	. . . . 5 |- ( -. x e. ( A i^i B ) <-> -. ( x e. A /\ x e. B ) )
14	13	anbi2i 457	. . . 4 |- ( ( x e. A /\ -. x e. ( A i^i B ) ) <-> ( x e. A /\ -. ( x e. A /\ x e. B ) ) )
15	11, 14	bitri 184	. . 3 |- ( x e. ( A \ ( A i^i B ) ) <-> ( x e. A /\ -. ( x e. A /\ x e. B ) ) )
16		eldif 3210	. . 3 |- ( x e. ( A \ B ) <-> ( x e. A /\ -. x e. B ) )
17	10, 15, 16	3bitr4i 212	. 2 |- ( x e. ( A \ ( A i^i B ) ) <-> x e. ( A \ B ) )
18	17	eqriv 2228	1 |- ( A \ ( A i^i B ) ) = ( A \ B )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 104   = wceq 1398   F. wfal 1403   e. wcel 2202   \ cdif 3198   i^i cin 3200

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 619  ax-in2 620  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-tru 1401  df-fal 1404  df-nf 1510  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-nfc 2364  df-v 2805  df-dif 3203  df-in 3207

This theorem is referenced by:  inssddif  3450  symdif1  3474  notrab  3486  disjdif2  3575  unfiin  7161  bj-charfundcALT  16525