Definition df-n0 9402

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 9401	. 2 class NN0
2		cn 9142	. . 3 class NN
3		cc0 8031	. . . 4 class 0
4	3	csn 3669	. . 3 class { 0 }
5	2, 4	cun 3198	. 2 class ( NN u. { 0 } )
6	1, 5	wceq 1397	1 wff NN0 = ( NN u. { 0 } )

This definition is referenced by:  elnn0  9403  nnssnn0  9404  nn0ssre  9405  nn0ex  9407  dfn2  9414  nn0addcl  9436  nn0mulcl  9437  nn0ssz  9496  dvdsprmpweqnn  12908