Definition df-xnn0 11364

Description: Define the set of extended nonnegative integers that includes positive infinity. Analogue of the extension of the real numbers RR*, see df-xr 10078. (Contributed by AV, 10-Dec-2020.)

Assertion

Ref	Expression
df-xnn0	|- NN0* = ( NN0 u. { +oo } )

Detailed syntax breakdown of Definition df-xnn0

Step	Hyp	Ref	Expression
1		cxnn0 11363	. 2 class NN0*
2		cn0 11292	. . 3 class NN0
3		cpnf 10071	. . . 4 class +oo
4	3	csn 4177	. . 3 class { +oo }
5	2, 4	cun 3572	. 2 class ( NN0 u. { +oo } )
6	1, 5	wceq 1483	1 wff NN0* = ( NN0 u. { +oo } )

This definition is referenced by:  elxnn0  11365  nn0ssxnn0  11366  hashfxnn0  13124  hashf  13125