Definition df-n0 9267

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 9266	. 2 class NN0
2		cn 9007	. . 3 class NN
3		cc0 7896	. . . 4 class 0
4	3	csn 3623	. . 3 class { 0 }
5	2, 4	cun 3155	. 2 class ( NN u. { 0 } )
6	1, 5	wceq 1364	1 wff NN0 = ( NN u. { 0 } )

This definition is referenced by:  elnn0  9268  nnssnn0  9269  nn0ssre  9270  nn0ex  9272  dfn2  9279  nn0addcl  9301  nn0mulcl  9302  nn0ssz  9361  dvdsprmpweqnn  12530