Theorem 1zs

Description: One is a surreal integer. (Contributed by Scott Fenton, 24-Jul-2025)

	Ref	Expression
Assertion	1zs	⊢ 1s ∈ ℤs

Proof

Step	Hyp	Ref	Expression
1		1n0s	⊢ 1s ∈ ℕ0s
2		n0zs	⊢ ( 1s ∈ ℕ0s → 1s ∈ ℤs )
3	1 2	ax-mp	⊢ 1s ∈ ℤs