Database REAL AND COMPLEX NUMBERS Construction and axiomatization of real and complex numbers Real and complex number postulates restated as axioms ax-rnegex  
				
		 
		
			
		 
		Description:   Existence of negative of real number.  Axiom 15 of 22 for real and
       complex numbers, justified by Theorem axrnegex  .  (Contributed by Eric
       Schmidt , 21-May-2007) 
		
			
				
					Ref 
					Expression 
				 
				
					Assertion 
					ax-rnegex    ⊢   A  ∈   ℝ     →   ∃  x  ∈   ℝ    A  +  x =   0            
				 
			
		 
		
				Detailed syntax breakdown 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							0 
								
							 
							cA  class  A    
						
							1 
								
							 
							cr  class   ℝ     
						
							2 
								0  1 
							 
							wcel  wff   A  ∈   ℝ       
						
							3 
								
							 
							vx  setvar  x    
						
							4 
								
							 
							caddc  class  +    
						
							5 
								3 
							 
							cv  setvar  x    
						
							6 
								0  5  4 
							 
							co  class  A  +  x    
						
							7 
								
							 
							cc0  class   0     
						
							8 
								6  7 
							 
							wceq  wff   A  +  x =   0       
						
							9 
								8  3  1 
							 
							wrex  wff   ∃  x  ∈   ℝ    A  +  x =   0         
						
							10 
								2  9 
							 
							wi  wff    A  ∈   ℝ     →   ∃  x  ∈   ℝ    A  +  x =   0