Metamath Proof Explorer
		
		
		
		Description:  The base set of a zero ring, a ring which is not a nonzero ring, is the
       singleton of the zero element.  (Contributed by AV, 17-Apr-2020)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | 0ring.b |  | 
					
						|  |  | 0ring.0 |  | 
				
					|  | Assertion | 0ringbas |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 0ring.b |  | 
						
							| 2 |  | 0ring.0 |  | 
						
							| 3 | 1 2 | 0ringdif |  | 
						
							| 4 | 3 | simprbi |  |