Definition df-n0 9499

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 9498	. 2 class NN0
2		cn 9239	. . 3 class NN
3		cc0 8129	. . . 4 class 0
4	3	csn 3691	. . 3 class { 0 }
5	2, 4	cun 3211	. 2 class ( NN u. { 0 } )
6	1, 5	wceq 1398	1 wff NN0 = ( NN u. { 0 } )

This definition is referenced by:  elnn0  9500  nnssnn0  9501  nn0ssre  9502  nn0ex  9504  dfn2  9511  nn0addcl  9533  nn0mulcl  9534  nn0ssz  9597  dvdsprmpweqnn  13038