Definition df-id 2125

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(s):   x,y

Detailed syntax breakdown of Definition df-id

Step	Hyp	Ref	Expression
1		cid 2057	. 2 class I
2		vx	. . . 4 set x
3		vy	. . . 4 set y
4	2, 3	weq 797	. . 3 wff x = y
5	4, 2, 3	copab 2055	. 2 class {<.x, y>. | x = y}
6	1, 5	wceq 1091	1 wff I = {<.x, y>. | x = y}

This definition is referenced by:  ideqg 2126  reli 2500  dffun2 2674

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