| Step | Hyp | Ref | Expression | 
						
							| 1 |  | erngset.h |  | 
						
							| 2 |  | elex |  | 
						
							| 3 |  | fveq2 |  | 
						
							| 4 | 3 1 | eqtr4di |  | 
						
							| 5 |  | fveq2 |  | 
						
							| 6 | 5 | fveq1d |  | 
						
							| 7 | 6 | opeq2d |  | 
						
							| 8 |  | fveq2 |  | 
						
							| 9 | 8 | fveq1d |  | 
						
							| 10 | 9 | mpteq1d |  | 
						
							| 11 | 6 6 10 | mpoeq123dv |  | 
						
							| 12 | 11 | opeq2d |  | 
						
							| 13 |  | eqidd |  | 
						
							| 14 | 6 6 13 | mpoeq123dv |  | 
						
							| 15 | 14 | opeq2d |  | 
						
							| 16 | 7 12 15 | tpeq123d |  | 
						
							| 17 | 4 16 | mpteq12dv |  | 
						
							| 18 |  | df-edring |  | 
						
							| 19 | 17 18 1 | mptfvmpt |  | 
						
							| 20 | 2 19 | syl |  |