Definition df-squarenn 37405

Description: Define the set of square positive integers. (Contributed by Stefan O'Rear, 18-Sep-2014.)

Assertion

Ref	Expression
df-squarenn	|- ◻NN = { x e. NN | ( sqr ` x ) e. QQ }

Detailed syntax breakdown of Definition df-squarenn

Step	Hyp	Ref	Expression
1		csquarenn 37400	. 2 class ◻NN
2		vx	. . . . . 6 setvar x
3	2	cv 1482	. . . . 5 class x
4		csqrt 13973	. . . . 5 class sqr
5	3, 4	cfv 5888	. . . 4 class ( sqr ` x )
6		cq 11788	. . . 4 class QQ
7	5, 6	wcel 1990	. . 3 wff ( sqr ` x ) e. QQ
8		cn 11020	. . 3 class NN
9	7, 2, 8	crab 2916	. 2 class { x e. NN | ( sqr ` x ) e. QQ }
10	1, 9	wceq 1483	1 wff ◻NN = { x e. NN | ( sqr ` x ) e. QQ }

This definition is referenced by:  pellqrex  37443  rmspecnonsq  37472