Theorem 0lt1o

Description: Ordinal zero is less than ordinal one. (Contributed by NM, 5-Jan-2005)

	Ref	Expression
Assertion	0lt1o	⊢ ∅ ∈ 1o

Proof

Step	Hyp	Ref	Expression
1		eqid	⊢ ∅ = ∅
2		el1o	⊢ ( ∅ ∈ 1o ↔ ∅ = ∅ )
3	1 2	mpbir	⊢ ∅ ∈ 1o