Database GRAPH THEORY Walks, paths and cycles Walks relwlk  
				
		 
		
			
		 
		Description:   The set ( Walks G )  of all walks on G  is a set of pairs by
       our definition of a walk, and so is a relation.  (Contributed by Alexander van der Vekens , 30-Jun-2018)   (Revised by AV , 19-Feb-2021) 
		
			
				
					Ref 
					Expression 
				 
				
					Assertion 
					relwlk   ⊢   Rel  ⁡   Walks  ⁡  G        
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							df-wlks  ⊢   Walks  =    g  ∈  V  ⟼   f  p |    f  ∈   Word   dom  ⁡    iEdg   ⁡  g         ∧   p  :   0   …  f ⟶    Vtx   ⁡  g     ∧   ∀  k  ∈   0   ..^  f  if-    p  ⁡  k   =   p  ⁡  k  +   1          iEdg   ⁡  g   ⁡   f  ⁡  k    =    p  ⁡  k          p  ⁡  k    p  ⁡  k  +   1      ⊆     iEdg   ⁡  g   ⁡   f  ⁡  k                    
						
							2 
								1 
							 
							relmptopab  ⊢   Rel  ⁡   Walks  ⁡  G