Metamath Proof Explorer
		
		
		
		Description:  Plus infinity exists.  (Contributed by David A. Wheeler, 8-Dec-2018)
     (Revised by Steven Nguyen, 7-Dec-2022)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | pnfex |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-pnf |  | 
						
							| 2 |  | cnex |  | 
						
							| 3 | 2 | uniex |  | 
						
							| 4 | 3 | pwex |  | 
						
							| 5 | 1 4 | eqeltri |  |