Theorem nnon

Description: A natural number is an ordinal number. (Contributed by NM, 27-Jun-1994)

	Ref	Expression
Assertion	nnon	⊢ ( 𝐴 ∈ ω → 𝐴 ∈ On )

Proof

Step	Hyp	Ref	Expression
1		omsson	⊢ ω ⊆ On
2	1	sseli	⊢ ( 𝐴 ∈ ω → 𝐴 ∈ On )