Metamath Proof Explorer
		
		
		
		Description:  The null graph (with no vertices and no edges) represented by the empty
     set is a complete simple graph.  (Contributed by AV, 1-Nov-2020)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | cusgr0 |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | usgr0 |  | 
						
							| 2 |  | cplgr0 |  | 
						
							| 3 |  | iscusgr |  | 
						
							| 4 | 1 2 3 | mpbir2an |  |