Theorem 1finon

Description: 1 is a finite ordinal. See 1onn . (Contributed by RP, 27-Sep-2023)

	Ref	Expression
Assertion	1finon	⊢ 1o ∈ ( On ∩ Fin )

Proof

Step	Hyp	Ref	Expression
1		1onn	⊢ 1o ∈ ω
2		onfin2	⊢ ω = ( On ∩ Fin )
3	1 2	eleqtri	⊢ 1o ∈ ( On ∩ Fin )