| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dvaset.h |  | 
						
							| 2 |  | elex |  | 
						
							| 3 |  | fveq2 |  | 
						
							| 4 | 3 1 | eqtr4di |  | 
						
							| 5 |  | fveq2 |  | 
						
							| 6 | 5 | fveq1d |  | 
						
							| 7 | 6 | opeq2d |  | 
						
							| 8 |  | eqidd |  | 
						
							| 9 | 6 6 8 | mpoeq123dv |  | 
						
							| 10 | 9 | opeq2d |  | 
						
							| 11 |  | fveq2 |  | 
						
							| 12 | 11 | fveq1d |  | 
						
							| 13 | 12 | opeq2d |  | 
						
							| 14 | 7 10 13 | tpeq123d |  | 
						
							| 15 |  | fveq2 |  | 
						
							| 16 | 15 | fveq1d |  | 
						
							| 17 |  | eqidd |  | 
						
							| 18 | 16 6 17 | mpoeq123dv |  | 
						
							| 19 | 18 | opeq2d |  | 
						
							| 20 | 19 | sneqd |  | 
						
							| 21 | 14 20 | uneq12d |  | 
						
							| 22 | 4 21 | mpteq12dv |  | 
						
							| 23 |  | df-dveca |  | 
						
							| 24 | 22 23 1 | mptfvmpt |  | 
						
							| 25 | 2 24 | syl |  |