Metamath Proof Explorer
		
		
		
		Description:  Subclass relation for a restricted class.  (Contributed by Glauco
       Siliprandi, 26-Jun-2021)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypothesis | ssrab2f.1 |  | 
				
					|  | Assertion | ssrab2f |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ssrab2f.1 |  | 
						
							| 2 |  | nfrab1 |  | 
						
							| 3 | 2 1 | dfss3f |  | 
						
							| 4 |  | rabidim1 |  | 
						
							| 5 | 3 4 | mprgbir |  |