| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cvmlift2.b |  |-  B = U. C | 
						
							| 2 |  | cvmlift2.f |  |-  ( ph -> F e. ( C CovMap J ) ) | 
						
							| 3 |  | cvmlift2.g |  |-  ( ph -> G e. ( ( II tX II ) Cn J ) ) | 
						
							| 4 |  | cvmlift2.p |  |-  ( ph -> P e. B ) | 
						
							| 5 |  | cvmlift2.i |  |-  ( ph -> ( F ` P ) = ( 0 G 0 ) ) | 
						
							| 6 |  | cvmlift2.h |  |-  H = ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( z G 0 ) ) /\ ( f ` 0 ) = P ) ) | 
						
							| 7 |  | cvmlift2.k |  |-  K = ( x e. ( 0 [,] 1 ) , y e. ( 0 [,] 1 ) |-> ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) /\ ( f ` 0 ) = ( H ` x ) ) ) ` y ) ) | 
						
							| 8 |  | oveq1 |  |-  ( x = X -> ( x G z ) = ( X G z ) ) | 
						
							| 9 | 8 | mpteq2dv |  |-  ( x = X -> ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) ) | 
						
							| 10 | 9 | eqeq2d |  |-  ( x = X -> ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) <-> ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) ) ) | 
						
							| 11 |  | fveq2 |  |-  ( x = X -> ( H ` x ) = ( H ` X ) ) | 
						
							| 12 | 11 | eqeq2d |  |-  ( x = X -> ( ( f ` 0 ) = ( H ` x ) <-> ( f ` 0 ) = ( H ` X ) ) ) | 
						
							| 13 | 10 12 | anbi12d |  |-  ( x = X -> ( ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) /\ ( f ` 0 ) = ( H ` x ) ) <-> ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ) | 
						
							| 14 | 13 | riotabidv |  |-  ( x = X -> ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) /\ ( f ` 0 ) = ( H ` x ) ) ) = ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ) | 
						
							| 15 | 14 | fveq1d |  |-  ( x = X -> ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( x G z ) ) /\ ( f ` 0 ) = ( H ` x ) ) ) ` y ) = ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ` y ) ) | 
						
							| 16 |  | fveq2 |  |-  ( y = Y -> ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ` y ) = ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ` Y ) ) | 
						
							| 17 |  | fvex |  |-  ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ` Y ) e. _V | 
						
							| 18 | 15 16 7 17 | ovmpo |  |-  ( ( X e. ( 0 [,] 1 ) /\ Y e. ( 0 [,] 1 ) ) -> ( X K Y ) = ( ( iota_ f e. ( II Cn C ) ( ( F o. f ) = ( z e. ( 0 [,] 1 ) |-> ( X G z ) ) /\ ( f ` 0 ) = ( H ` X ) ) ) ` Y ) ) |