Theorem 2iunin 4034

Description: Rearrange indexed unions over intersection. (Contributed by NM, 18-Dec-2008.)

Assertion

Ref	Expression
2iunin	|- U_x e. A U_y e. B (C i^i D) = (U_x e. A C i^i U_y e. B D)

Distinct variable groups:   x,B   y,C   x,D   x,y

Allowed substitution hints:   A(x,y)   B(y)   C(x)   D(y)

Proof of Theorem 2iunin

Step	Hyp	Ref	Expression
1		iunin2 4030	. . . 4 |- U_y e. B (C i^i D) = (C i^i U_y e. B D)
2	1	a1i 10	. . 3 |- (x e. A -> U_y e. B (C i^i D) = (C i^i U_y e. B D))
3	2	iuneq2i 3987	. 2 |- U_x e. A U_y e. B (C i^i D) = U_x e. A (C i^i U_y e. B D)
4		iunin1 4031	. 2 |- U_x e. A (C i^i U_y e. B D) = (U_x e. A C i^i U_y e. B D)
5	3, 4	eqtri 2373	1 |- U_x e. A U_y e. B (C i^i D) = (U_x e. A C i^i U_y e. B D)

Syntax hints:   = wceq 1642   e. wcel 1710   i^i cin 3208  U_ciun 3969

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 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-ral 2619  df-rex 2620  df-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-ss 3259  df-iun 3971

This theorem is referenced by: (None)