Database BASIC STRUCTURES Extensible structures Basic definitions Base sets 2strstr  
				
		 
		
			
		 
		Description:   A constructed two-slot structure.  Depending on hard-coded indices.  Use
       2strstr1  instead.  (Contributed by Mario Carneiro , 29-Aug-2015) 
       (New usage is discouraged.) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						2str.g   ⊢   G  =    Base  ndx B      E  ⁡  ndx   +  ˙          
					 
					
						2str.e   ⊢   E  =  Slot  N       
					 
					
						2str.l   ⊢    1   <  N       
					 
					
						2str.n   ⊢   N  ∈   ℕ        
					 
				
					Assertion 
					2strstr   ⊢  G  Struct    1   N      
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							2str.g  ⊢   G  =    Base  ndx B      E  ⁡  ndx   +  ˙          
						
							2 
								
							 
							2str.e  ⊢   E  =  Slot  N       
						
							3 
								
							 
							2str.l  ⊢    1   <  N       
						
							4 
								
							 
							2str.n  ⊢   N  ∈   ℕ        
						
							5 
								
							 
							1nn  ⊢    1   ∈   ℕ        
						
							6 
								
							 
							basendx  ⊢   Base  ndx =   1        
						
							7 
								2  4 
							 
							ndxarg  ⊢    E  ⁡  ndx   =  N       
						
							8 
								5  6  3  4  7 
							 
							strle2  ⊢    Base  ndx B      E  ⁡  ndx   +  ˙     Struct    1   N      
						
							9 
								1  8 
							 
							eqbrtri  ⊢  G  Struct    1   N