Metamath Proof Explorer


Theorem nnsgt0

Description: A positive integer is greater than zero. (Contributed by Scott Fenton, 15-Apr-2025)

Ref Expression
Assertion nnsgt0 ⊢ A ∈ ℕ s → 0 s < s A

Proof

Step Hyp Ref Expression
1 nnssn0s ⊢ ℕ s ⊆ ℕ 0s
2 1 sseli ⊢ A ∈ ℕ s → A ∈ ℕ 0s
3 n0sge0 ⊢ A ∈ ℕ 0s → 0 s ≤ s A
4 2 3 syl ⊢ A ∈ ℕ s → 0 s ≤ s A
5 nnne0s ⊢ A ∈ ℕ s → A ≠ 0 s
6 0no ⊢ 0 s ∈ No
7 6 a1i ⊢ A ∈ ℕ s → 0 s ∈ No
8 nnno ⊢ A ∈ ℕ s → A ∈ No
9 7 8 ltlesnd ⊢ A ∈ ℕ s → 0 s < s A ↔ 0 s ≤ s A ∧ A ≠ 0 s
10 4 5 9 mpbir2and ⊢ A ∈ ℕ s → 0 s < s A