Theorem addsridd

Description: Surreal addition to zero is identity. Part of Theorem 3 of Conway p. 17. (Contributed by Scott Fenton, 20-Aug-2024)

	Ref	Expression
Hypothesis	addsridd.1	|- ( ph -> A e. No )
Assertion	addsridd	|- ( ph -> ( A +s 0s ) = A )

Proof

Step	Hyp	Ref	Expression
1		addsridd.1	|- ( ph -> A e. No )
2		addsrid	|- ( A e. No -> ( A +s 0s ) = A )
3	1 2	syl	|- ( ph -> ( A +s 0s ) = A )