Theorem difundi 3508

Description: Distributive law for class difference. Theorem 39 of [Suppes] p. 29. (Contributed by NM, 17-Aug-2004.)

Assertion

Ref	Expression
difundi	|- (A \ (B u. C)) = ((A \ B) i^i (A \ C))

Proof of Theorem difundi

Step	Hyp	Ref	Expression
1		dfun3 3494	. . 3 |- (B u. C) = (_V \ ((_V \ B) i^i (_V \ C)))
2	1	difeq2i 3383	. 2 |- (A \ (B u. C)) = (A \ (_V \ ((_V \ B) i^i (_V \ C))))
3		inindi 3473	. . 3 |- (A i^i ((_V \ B) i^i (_V \ C))) = ((A i^i (_V \ B)) i^i (A i^i (_V \ C)))
4		dfin2 3492	. . 3 |- (A i^i ((_V \ B) i^i (_V \ C))) = (A \ (_V \ ((_V \ B) i^i (_V \ C))))
5		invdif 3497	. . . 4 |- (A i^i (_V \ B)) = (A \ B)
6		invdif 3497	. . . 4 |- (A i^i (_V \ C)) = (A \ C)
7	5, 6	ineq12i 3456	. . 3 |- ((A i^i (_V \ B)) i^i (A i^i (_V \ C))) = ((A \ B) i^i (A \ C))
8	3, 4, 7	3eqtr3i 2381	. 2 |- (A \ (_V \ ((_V \ B) i^i (_V \ C)))) = ((A \ B) i^i (A \ C))
9	2, 8	eqtri 2373	1 |- (A \ (B u. C)) = ((A \ B) i^i (A \ C))

Syntax hints:   = wceq 1642  _Vcvv 2860   \ cdif 3207   u. cun 3208   i^i cin 3209

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 2479  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216

This theorem is referenced by:  undm  3513