Metamath Proof Explorer
		
		
		
		Description:  Closure of exponentiation of nonnegative integers.  (Contributed by Mario Carneiro, 17-Apr-2015)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | nn0expcli.1 |  | 
					
						|  |  | nn0expcli.2 |  | 
				
					|  | Assertion | nn0expcli |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nn0expcli.1 |  | 
						
							| 2 |  | nn0expcli.2 |  | 
						
							| 3 |  | nn0expcl |  | 
						
							| 4 | 1 2 3 | mp2an |  |