Definition df-xnn0 11969

Description: Define the set of extended nonnegative integers that includes positive infinity. Analogue of the extension of the real numbers ℝ^*, see df-xr 10679. (Contributed by AV, 10-Dec-2020.)

Assertion

Ref	Expression
df-xnn0	⊢ ℕ0* = (ℕ0 ∪ {+∞})

Detailed syntax breakdown of Definition df-xnn0

Step	Hyp	Ref	Expression
1		cxnn0 11968	. 2 class ℕ0*
2		cn0 11898	. . 3 class ℕ0
3		cpnf 10672	. . . 4 class +∞
4	3	csn 4567	. . 3 class {+∞}
5	2, 4	cun 3934	. 2 class (ℕ0 ∪ {+∞})
6	1, 5	wceq 1537	1 wff ℕ0* = (ℕ0 ∪ {+∞})

This definition is referenced by:  elxnn0  11970  nn0ssxnn0  11971  hashfxnn0  13698  hashf  13699