Definition df-id 2830

Description: Define the identity relation. Definition 9.15 of [Quine] p. 64.

Assertion

Ref	Expression
df-id	|- I = {<.x, y>. | x = y}

Distinct variable group:   x,y

Detailed syntax breakdown of Definition df-id

Step	Hyp	Ref	Expression
1		cid 2826	. 2 class I
2		vx	. . . . 5 set x
3	2	cv 953	. . . 4 class x
4		vy	. . . . 5 set y
5	4	cv 953	. . . 4 class y
6	3, 5	wceq 954	. . 3 wff x = y
7	6, 2, 4	copab 2661	. 2 class {<.x, y>. | x = y}
8	1, 7	wceq 954	1 wff I = {<.x, y>. | x = y}

This definition is referenced by:  dfid3 2831  reli 3268  ideqg 3271  dffun2 3518

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