Definition df-xnn0 12020

Description: Define the set of extended nonnegative integers that includes positive infinity. Analogue of the extension of the real numbers ℝ^*, see df-xr 10730. (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 12019	. 2 class ℕ0*
2		cn0 11947	. . 3 class ℕ0
3		cpnf 10723	. . . 4 class +∞
4	3	csn 4525	. . 3 class {+∞}
5	2, 4	cun 3858	. 2 class (ℕ0 ∪ {+∞})
6	1, 5	wceq 1538	1 wff ℕ0* = (ℕ0 ∪ {+∞})

This definition is referenced by:  elxnn0  12021  nn0ssxnn0  12022  hashfxnn0  13760  hashf  13761