Database GRAPH THEORY Vertices and edges Vertices and indexed edges The vertices and edges of a graph represented as extensible structure grstructeld  
				
		 
		
			
		 
		Description:   If any representation of a graph with vertices V  and edges E  is
       an element of an arbitrary class C  , then any structure with base
       set V  and value E  in the slot for edge functions (which is such
       a representation of a graph with vertices V  and edges E  ) is an
       element of this class C  .  (Contributed by AV , 12-Oct-2020) 
       (Revised by AV , 9-Jun-2021) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						gropeld.g    ⊢   φ   →   ∀  g       Vtx   ⁡  g   =  V    ∧     iEdg   ⁡  g   =  E     →   g  ∈  C            
					 
					
						gropeld.v    ⊢   φ   →   V  ∈  U         
					 
					
						gropeld.e    ⊢   φ   →   E  ∈  W         
					 
					
						grstructeld.s    ⊢   φ   →   S  ∈  X         
					 
					
						grstructeld.f    ⊢   φ   →   Fun  ⁡   S  ∖   ∅            
					 
					
						grstructeld.d    ⊢   φ   →    2   ≤   dom  ⁡  S          
					 
					
						grstructeld.b    ⊢   φ   →   Base  S =  V         
					 
					
						grstructeld.e    ⊢   φ   →     ef   ⁡  S   =  E         
					 
				
					Assertion 
					grstructeld    ⊢   φ   →   S  ∈  C         
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							gropeld.g   ⊢   φ   →   ∀  g       Vtx   ⁡  g   =  V    ∧     iEdg   ⁡  g   =  E     →   g  ∈  C            
						
							2 
								
							 
							gropeld.v   ⊢   φ   →   V  ∈  U         
						
							3 
								
							 
							gropeld.e   ⊢   φ   →   E  ∈  W         
						
							4 
								
							 
							grstructeld.s   ⊢   φ   →   S  ∈  X         
						
							5 
								
							 
							grstructeld.f   ⊢   φ   →   Fun  ⁡   S  ∖   ∅            
						
							6 
								
							 
							grstructeld.d   ⊢   φ   →    2   ≤   dom  ⁡  S          
						
							7 
								
							 
							grstructeld.b   ⊢   φ   →   Base  S =  V         
						
							8 
								
							 
							grstructeld.e   ⊢   φ   →     ef   ⁡  S   =  E         
						
							9 
								1  2  3  4  5  6  7  8 
							 
							grstructd   ⊢   φ   →  [ ˙ S  /  g ] ˙  g  ∈  C        
						
							10 
								
							 
							sbcel1v   ⊢  [ ˙ S  /  g ] ˙  g  ∈  C   ↔   S  ∈  C         
						
							11 
								9  10 
							 
							sylib   ⊢   φ   →   S  ∈  C