Definition df-n0 8830

Description: Define the set of nonnegative integers. (Contributed by Raph Levien, 10-Dec-2002.)

Assertion

Ref	Expression
df-n0	⊢ ℕ0 = (ℕ ∪ {0})

Detailed syntax breakdown of Definition df-n0

Step	Hyp	Ref	Expression
1		cn0 8829	. 2 class ℕ0
2		cn 8578	. . 3 class ℕ
3		cc0 7500	. . . 4 class 0
4	3	csn 3474	. . 3 class {0}
5	2, 4	cun 3019	. 2 class (ℕ ∪ {0})
6	1, 5	wceq 1299	1 wff ℕ0 = (ℕ ∪ {0})

This definition is referenced by:  elnn0  8831  nnssnn0  8832  nn0ssre  8833  nn0ex  8835  dfn2  8842  nn0addcl  8864  nn0mulcl  8865  nn0ssz  8924