Theorem ontrciOLD

Description: Obsolete version of ontr as of 28-Dec-2024. (Contributed by NM, 11-Jun-1994) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	on.1	⊢ 𝐴 ∈ On
Assertion	ontrciOLD	⊢ Tr 𝐴

Proof

Step	Hyp	Ref	Expression
1		on.1	⊢ 𝐴 ∈ On
2		ontr	⊢ ( 𝐴 ∈ On → Tr 𝐴 )
3	1 2	ax-mp	⊢ Tr 𝐴