Description: A surreal positive integer is non-zero. (Contributed by Scott Fenton, 15-Apr-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | nnne0s | ⊢ ( 𝐴 ∈ ℕs → 𝐴 ≠ 0s ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eldifsni | ⊢ ( 𝐴 ∈ ( ℕ0s ∖ { 0s } ) → 𝐴 ≠ 0s ) | |
| 2 | df-nns | ⊢ ℕs = ( ℕ0s ∖ { 0s } ) | |
| 3 | 1 2 | eleq2s | ⊢ ( 𝐴 ∈ ℕs → 𝐴 ≠ 0s ) |