Theorem onnoi

Description: Every ordinal maps to a surreal number. (Contributed by RP, 21-Sep-2023)

	Ref	Expression
Hypothesis	onnoi.on	|- A e. On
Assertion	onnoi	|- ( A X. { 2o } ) e. No

Proof

Step	Hyp	Ref	Expression
1		onnoi.on	|- A e. On
2		onno	|- ( A e. On -> ( A X. { 2o } ) e. No )
3	1 2	ax-mp	|- ( A X. { 2o } ) e. No