Database REAL AND COMPLEX NUMBERS Real and complex numbers - basic operations Reciprocals mulne0bad  
				
		 
		
			
		 
		Description:   A factor of a nonzero complex number is nonzero.  Partial converse of
       mulne0d  and consequence of mulne0bd  .  (Contributed by David Moews , 28-Feb-2017) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						mulne0bad.1    ⊢   φ   →   A  ∈   ℂ          
					 
					
						mulne0bad.2    ⊢   φ   →   B  ∈   ℂ          
					 
					
						mulne0bad.3    ⊢   φ   →    A  ⁢  B    ≠   0          
					 
				
					Assertion 
					mulne0bad    ⊢   φ   →   A  ≠   0          
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							mulne0bad.1   ⊢   φ   →   A  ∈   ℂ          
						
							2 
								
							 
							mulne0bad.2   ⊢   φ   →   B  ∈   ℂ          
						
							3 
								
							 
							mulne0bad.3   ⊢   φ   →    A  ⁢  B    ≠   0          
						
							4 
								1  2 
							 
							mulne0bd   ⊢   φ   →     A  ≠   0     ∧   B  ≠   0      ↔    A  ⁢  B    ≠   0           
						
							5 
								3  4 
							 
							mpbird   ⊢   φ   →    A  ≠   0     ∧   B  ≠   0           
						
							6 
								5 
							 
							simpld   ⊢   φ   →   A  ≠   0