Metamath Proof Explorer


Definition df-squarenn

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

Ref Expression
Assertion df-squarenn
|- []NN = { x e. NN | ( sqrt ` x ) e. QQ }

Detailed syntax breakdown

Step Hyp Ref Expression
0 csquarenn
 |-  []NN
1 vx
 |-  x
2 cn
 |-  NN
3 csqrt
 |-  sqrt
4 1 cv
 |-  x
5 4 3 cfv
 |-  ( sqrt ` x )
6 cq
 |-  QQ
7 5 6 wcel
 |-  ( sqrt ` x ) e. QQ
8 7 1 2 crab
 |-  { x e. NN | ( sqrt ` x ) e. QQ }
9 0 8 wceq
 |-  []NN = { x e. NN | ( sqrt ` x ) e. QQ }