Definition df-iin 3971

Description: Define indexed intersection. Definition of [Stoll] p. 45. See the remarks for its sibling operation of indexed union df-iun 3970. An alternate definition tying indexed intersection to ordinary intersection is dfiin2 4003. Theorem intiin 4023 provides a definition of ordinary intersection in terms of indexed intersection. (Contributed by NM, 27-Jun-1998.)

Assertion

Ref	Expression
df-iin	|- |^|_ x e. A B = { y | A. x e. A y e. B }

Distinct variable groups:   x, y   y, A   y, B

Allowed substitution hints:   A( x)   B( x)

Detailed syntax breakdown of Definition df-iin

Step	Hyp	Ref	Expression
1		vx	. . 3 setvar x
2		cA	. . 3 class A
3		cB	. . 3 class B
4	1, 2, 3	ciin 3969	. 2 class |^|_ x e. A B
5		vy	. . . . . 6 setvar y
6	5	cv 1394	. . . . 5 class y
7	6, 3	wcel 2200	. . . 4 wff y e. B
8	7, 1, 2	wral 2508	. . 3 wff A. x e. A y e. B
9	8, 5	cab 2215	. 2 class { y | A. x e. A y e. B }
10	4, 9	wceq 1395	1 wff |^|_ x e. A B = { y | A. x e. A y e. B }

This definition is referenced by:  eliin  3973  iineq1  3982  iineq2  3985  nfiinxy  3995  nfiinya  3997  nfii1  3999  dfiin2g  4001  cbviin  4006  intiin  4023  0iin  4027  viin  4028  iinxsng  4042  iinxprg  4043  iinuniss  4051  bdciin  16410