Theorem rightirr

Description: No surreal is a member of its right set. (Contributed by Scott Fenton, 9-Oct-2024)

	Ref	Expression
Assertion	rightirr	⊢ ¬ 𝑋 ∈ ( R ‘ 𝑋 )

Proof

Step	Hyp	Ref	Expression
1		oldirr	⊢ ¬ 𝑋 ∈ ( O ‘ ( bday ‘ 𝑋 ) )
2		rightssold	⊢ ( R ‘ 𝑋 ) ⊆ ( O ‘ ( bday ‘ 𝑋 ) )
3	2	sseli	⊢ ( 𝑋 ∈ ( R ‘ 𝑋 ) → 𝑋 ∈ ( O ‘ ( bday ‘ 𝑋 ) ) )
4	1 3	mto	⊢ ¬ 𝑋 ∈ ( R ‘ 𝑋 )