Theorem 1ons

Description: Surreal one is a surreal ordinal. (Contributed by Scott Fenton, 18-Mar-2025)

	Ref	Expression
Assertion	1ons	Could not format assertion : No typesetting found for |- 1s e. On_s with typecode |-

Proof

Step	Hyp	Ref	Expression
1		1sno	Could not format 1s e. No : No typesetting found for |- 1s e. No with typecode |-
2		right1s	Could not format ( _Right ` 1s ) = (/) : No typesetting found for |- ( _Right ` 1s ) = (/) with typecode |-
3		elons	Could not format ( 1s e. On_s <-> ( 1s e. No /\ ( _Right ` 1s ) = (/) ) ) : No typesetting found for |- ( 1s e. On_s <-> ( 1s e. No /\ ( _Right ` 1s ) = (/) ) ) with typecode |-
4	1 2 3	mpbir2an	Could not format 1s e. On_s : No typesetting found for |- 1s e. On_s with typecode |-