Definition df-sset 4726

Description: Define a relationship that holds between subsets. (Contributed by SF, 5-Jan-2015.)

Assertion

Ref	Expression
df-sset	|- S = {<.x, y>. | x C_ y}

Distinct variable group:   x,y

Detailed syntax breakdown of Definition df-sset

Step	Hyp	Ref	Expression
1		csset 4720	. 2 class S
2		vx	. . . . 5 setvar x
3	2	cv 1641	. . . 4 class x
4		vy	. . . . 5 setvar y
5	4	cv 1641	. . . 4 class y
6	3, 5	wss 3258	. . 3 wff x C_ y
7	6, 2, 4	copab 4623	. 2 class {<.x, y>. | x C_ y}
8	1, 7	wceq 1642	1 wff S = {<.x, y>. | x C_ y}

This definition is referenced by:  dfsset2  4744  brssetg  4758