Metamath Proof Explorer
		
		
		
		Description:  Addition of positive and nonnegative numbers is positive.
         (Contributed by Asger C. Ipsen, 12-May-2021)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | leidd.1 | ⊢ ( 𝜑  →  𝐴  ∈  ℝ ) | 
					
						|  |  | ltnegd.2 | ⊢ ( 𝜑  →  𝐵  ∈  ℝ ) | 
					
						|  |  | addgtge0d.3 | ⊢ ( 𝜑  →  0  <  𝐴 ) | 
					
						|  |  | addgtge0d.4 | ⊢ ( 𝜑  →  0  ≤  𝐵 ) | 
				
					|  | Assertion | addgtge0d | ⊢  ( 𝜑  →  0  <  ( 𝐴  +  𝐵 ) ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | leidd.1 | ⊢ ( 𝜑  →  𝐴  ∈  ℝ ) | 
						
							| 2 |  | ltnegd.2 | ⊢ ( 𝜑  →  𝐵  ∈  ℝ ) | 
						
							| 3 |  | addgtge0d.3 | ⊢ ( 𝜑  →  0  <  𝐴 ) | 
						
							| 4 |  | addgtge0d.4 | ⊢ ( 𝜑  →  0  ≤  𝐵 ) | 
						
							| 5 |  | addgtge0 | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  𝐵  ∈  ℝ )  ∧  ( 0  <  𝐴  ∧  0  ≤  𝐵 ) )  →  0  <  ( 𝐴  +  𝐵 ) ) | 
						
							| 6 | 1 2 3 4 5 | syl22anc | ⊢ ( 𝜑  →  0  <  ( 𝐴  +  𝐵 ) ) |