| Step | Hyp | Ref | Expression | 
						
							| 1 |  | xkoval.x |  | 
						
							| 2 |  | xkoval.k |  | 
						
							| 3 |  | xkoval.t |  | 
						
							| 4 |  | simpr |  | 
						
							| 5 | 4 | unieqd |  | 
						
							| 6 | 5 1 | eqtr4di |  | 
						
							| 7 | 6 | pweqd |  | 
						
							| 8 | 4 | oveq1d |  | 
						
							| 9 | 8 | eleq1d |  | 
						
							| 10 | 7 9 | rabeqbidv |  | 
						
							| 11 | 10 2 | eqtr4di |  | 
						
							| 12 |  | simpl |  | 
						
							| 13 | 4 12 | oveq12d |  | 
						
							| 14 | 13 | rabeqdv |  | 
						
							| 15 | 11 12 14 | mpoeq123dv |  | 
						
							| 16 | 15 3 | eqtr4di |  | 
						
							| 17 | 16 | rneqd |  | 
						
							| 18 | 17 | fveq2d |  | 
						
							| 19 | 18 | fveq2d |  | 
						
							| 20 |  | df-xko |  | 
						
							| 21 |  | fvex |  | 
						
							| 22 | 19 20 21 | ovmpoa |  | 
						
							| 23 | 22 | ancoms |  |