Metamath Proof Explorer
		
		
		
		Description:  Division of both sides of 'less than' by a positive number.
         (Contributed by NM, 16-May-1999)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | ltplus1.1 | ⊢ 𝐴  ∈  ℝ | 
					
						|  |  | prodgt0.2 | ⊢ 𝐵  ∈  ℝ | 
					
						|  |  | ltmul1.3 | ⊢ 𝐶  ∈  ℝ | 
					
						|  |  | ltmul1i.4 | ⊢ 0  <  𝐶 | 
				
					|  | Assertion | ltdiv1ii | ⊢  ( 𝐴  <  𝐵  ↔  ( 𝐴  /  𝐶 )  <  ( 𝐵  /  𝐶 ) ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ltplus1.1 | ⊢ 𝐴  ∈  ℝ | 
						
							| 2 |  | prodgt0.2 | ⊢ 𝐵  ∈  ℝ | 
						
							| 3 |  | ltmul1.3 | ⊢ 𝐶  ∈  ℝ | 
						
							| 4 |  | ltmul1i.4 | ⊢ 0  <  𝐶 | 
						
							| 5 | 1 2 3 | ltdiv1i | ⊢ ( 0  <  𝐶  →  ( 𝐴  <  𝐵  ↔  ( 𝐴  /  𝐶 )  <  ( 𝐵  /  𝐶 ) ) ) | 
						
							| 6 | 4 5 | ax-mp | ⊢ ( 𝐴  <  𝐵  ↔  ( 𝐴  /  𝐶 )  <  ( 𝐵  /  𝐶 ) ) |