Definition df-n0 9115

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 9114	. 2 class NN0
2		cn 8857	. . 3 class NN
3		cc0 7753	. . . 4 class 0
4	3	csn 3576	. . 3 class { 0 }
5	2, 4	cun 3114	. 2 class ( NN u. { 0 } )
6	1, 5	wceq 1343	1 wff NN0 = ( NN u. { 0 } )

This definition is referenced by:  elnn0  9116  nnssnn0  9117  nn0ssre  9118  nn0ex  9120  dfn2  9127  nn0addcl  9149  nn0mulcl  9150  nn0ssz  9209  dvdsprmpweqnn  12267