Metamath Proof Explorer
		
		
		
		Description:  A positive integer is greater than zero.  (Contributed by Scott Fenton, 15-Apr-2025)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | nnsgt0 | ⊢  ( 𝐴  ∈  ℕs  →   0s   <s  𝐴 ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nnssn0s | ⊢ ℕs  ⊆  ℕ0s | 
						
							| 2 | 1 | sseli | ⊢ ( 𝐴  ∈  ℕs  →  𝐴  ∈  ℕ0s ) | 
						
							| 3 |  | n0sge0 | ⊢ ( 𝐴  ∈  ℕ0s  →   0s   ≤s  𝐴 ) | 
						
							| 4 | 2 3 | syl | ⊢ ( 𝐴  ∈  ℕs  →   0s   ≤s  𝐴 ) | 
						
							| 5 |  | nnne0s | ⊢ ( 𝐴  ∈  ℕs  →  𝐴  ≠   0s  ) | 
						
							| 6 |  | 0sno | ⊢  0s   ∈   No | 
						
							| 7 | 6 | a1i | ⊢ ( 𝐴  ∈  ℕs  →   0s   ∈   No  ) | 
						
							| 8 |  | nnsno | ⊢ ( 𝐴  ∈  ℕs  →  𝐴  ∈   No  ) | 
						
							| 9 | 7 8 | sltlend | ⊢ ( 𝐴  ∈  ℕs  →  (  0s   <s  𝐴  ↔  (  0s   ≤s  𝐴  ∧  𝐴  ≠   0s  ) ) ) | 
						
							| 10 | 4 5 9 | mpbir2and | ⊢ ( 𝐴  ∈  ℕs  →   0s   <s  𝐴 ) |