Database SUPPLEMENTARY MATERIAL (USERS' MATHBOXES) Mathbox for Alan Sare Virtual Deduction Theorems e002  
				
		 
		
			
		 
		Description:   A virtual deduction elimination rule.  (Contributed by Alan Sare , 24-Jun-2011)   (Proof modification is discouraged.) 
       (New usage is discouraged.) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						e002.1   ⊢   φ      
					 
					
						e002.2   ⊢   ψ      
					 
					
						e002.3   ⊢   χ   ,   θ   →   τ     
					 
					
						e002.4    ⊢   φ   →    ψ   →    τ   →   η          
					 
				
					Assertion 
					e002   ⊢   χ   ,   θ   →   η     
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							e002.1  ⊢   φ      
						
							2 
								
							 
							e002.2  ⊢   ψ      
						
							3 
								
							 
							e002.3  ⊢   χ   ,   θ   →   τ     
						
							4 
								
							 
							e002.4   ⊢   φ   →    ψ   →    τ   →   η          
						
							5 
								1 
							 
							vd02  ⊢   χ   ,   θ   →   φ     
						
							6 
								2 
							 
							vd02  ⊢   χ   ,   θ   →   ψ     
						
							7 
								5  6  3  4 
							 
							e222  ⊢   χ   ,   θ   →   η