| Step | Hyp | Ref | Expression | 
						
							| 1 |  | istmd.1 |  | 
						
							| 2 |  | istmd.2 |  | 
						
							| 3 |  | elin |  | 
						
							| 4 | 3 | anbi1i |  | 
						
							| 5 |  | fvexd |  | 
						
							| 6 |  | simpl |  | 
						
							| 7 | 6 | fveq2d |  | 
						
							| 8 | 7 1 | eqtr4di |  | 
						
							| 9 |  | id |  | 
						
							| 10 |  | fveq2 |  | 
						
							| 11 | 10 2 | eqtr4di |  | 
						
							| 12 | 9 11 | sylan9eqr |  | 
						
							| 13 | 12 12 | oveq12d |  | 
						
							| 14 | 13 12 | oveq12d |  | 
						
							| 15 | 8 14 | eleq12d |  | 
						
							| 16 | 5 15 | sbcied |  | 
						
							| 17 |  | df-tmd |  | 
						
							| 18 | 16 17 | elrab2 |  | 
						
							| 19 |  | df-3an |  | 
						
							| 20 | 4 18 19 | 3bitr4i |  |