| Step | Hyp | Ref | Expression | 
						
							| 1 |  | imasbas.u |  | 
						
							| 2 |  | imasbas.v |  | 
						
							| 3 |  | imasbas.f |  | 
						
							| 4 |  | imasbas.r |  | 
						
							| 5 |  | imasds.e |  | 
						
							| 6 |  | imasds.d |  | 
						
							| 7 |  | imasdsval.x |  | 
						
							| 8 |  | imasdsval.y |  | 
						
							| 9 |  | imasdsval.s |  | 
						
							| 10 |  | imasds.u |  | 
						
							| 11 | 1 2 3 4 5 6 7 8 9 | imasdsval |  | 
						
							| 12 | 10 | coeq1i |  | 
						
							| 13 | 9 | ssrab3 |  | 
						
							| 14 | 13 | sseli |  | 
						
							| 15 |  | elmapi |  | 
						
							| 16 |  | frn |  | 
						
							| 17 |  | cores |  | 
						
							| 18 | 14 15 16 17 | 4syl |  | 
						
							| 19 | 12 18 | eqtrid |  | 
						
							| 20 | 19 | oveq2d |  | 
						
							| 21 | 20 | mpteq2ia |  | 
						
							| 22 | 21 | rneqi |  | 
						
							| 23 | 22 | a1i |  | 
						
							| 24 | 23 | iuneq2i |  | 
						
							| 25 | 24 | infeq1i |  | 
						
							| 26 | 11 25 | eqtr4di |  |