Definition df-n0 9546

Description: Define the set of nonnegative integers. (Contributed by Raph Levien, 10-Dec-2002.)

Assertion

Ref	Expression
df-n0	|- NN0 = ( NN u. { 0 } )

Detailed syntax breakdown of Definition df-n0

Step	Hyp	Ref	Expression
1		cn0 9545	. 2 class NN0
2		cn 9286	. . 3 class NN
3		cc0 8172	. . . 4 class 0
4	3	csn 3708	. . 3 class { 0 }
5	2, 4	cun 3218	. 2 class ( NN u. { 0 } )
6	1, 5	wceq 1402	1 wff NN0 = ( NN u. { 0 } )

This definition is referenced by:  elnn0  9547  nnssnn0  9548  nn0ssre  9549  nn0ex  9551  dfn2  9558  nn0addcl  9580  nn0mulcl  9581  nn0ssz  9644  dvdsprmpweqnn  13096