| Step | Hyp | Ref | Expression | 
						
							| 1 |  | onovuni.1 |  |-  ( Lim y -> ( A F y ) = U_ x e. y ( A F x ) ) | 
						
							| 2 |  | onovuni.2 |  |-  ( ( x e. On /\ y e. On /\ x C_ y ) -> ( A F x ) C_ ( A F y ) ) | 
						
							| 3 |  | oveq2 |  |-  ( z = y -> ( A F z ) = ( A F y ) ) | 
						
							| 4 |  | eqid |  |-  ( z e. _V |-> ( A F z ) ) = ( z e. _V |-> ( A F z ) ) | 
						
							| 5 |  | ovex |  |-  ( A F y ) e. _V | 
						
							| 6 | 3 4 5 | fvmpt |  |-  ( y e. _V -> ( ( z e. _V |-> ( A F z ) ) ` y ) = ( A F y ) ) | 
						
							| 7 | 6 | elv |  |-  ( ( z e. _V |-> ( A F z ) ) ` y ) = ( A F y ) | 
						
							| 8 |  | oveq2 |  |-  ( z = x -> ( A F z ) = ( A F x ) ) | 
						
							| 9 |  | ovex |  |-  ( A F x ) e. _V | 
						
							| 10 | 8 4 9 | fvmpt |  |-  ( x e. _V -> ( ( z e. _V |-> ( A F z ) ) ` x ) = ( A F x ) ) | 
						
							| 11 | 10 | elv |  |-  ( ( z e. _V |-> ( A F z ) ) ` x ) = ( A F x ) | 
						
							| 12 | 11 | a1i |  |-  ( x e. y -> ( ( z e. _V |-> ( A F z ) ) ` x ) = ( A F x ) ) | 
						
							| 13 | 12 | iuneq2i |  |-  U_ x e. y ( ( z e. _V |-> ( A F z ) ) ` x ) = U_ x e. y ( A F x ) | 
						
							| 14 | 1 7 13 | 3eqtr4g |  |-  ( Lim y -> ( ( z e. _V |-> ( A F z ) ) ` y ) = U_ x e. y ( ( z e. _V |-> ( A F z ) ) ` x ) ) | 
						
							| 15 | 2 11 7 | 3sstr4g |  |-  ( ( x e. On /\ y e. On /\ x C_ y ) -> ( ( z e. _V |-> ( A F z ) ) ` x ) C_ ( ( z e. _V |-> ( A F z ) ) ` y ) ) | 
						
							| 16 | 14 15 | onfununi |  |-  ( ( S e. T /\ S C_ On /\ S =/= (/) ) -> ( ( z e. _V |-> ( A F z ) ) ` U. S ) = U_ x e. S ( ( z e. _V |-> ( A F z ) ) ` x ) ) | 
						
							| 17 |  | uniexg |  |-  ( S e. T -> U. S e. _V ) | 
						
							| 18 |  | oveq2 |  |-  ( z = U. S -> ( A F z ) = ( A F U. S ) ) | 
						
							| 19 |  | ovex |  |-  ( A F U. S ) e. _V | 
						
							| 20 | 18 4 19 | fvmpt |  |-  ( U. S e. _V -> ( ( z e. _V |-> ( A F z ) ) ` U. S ) = ( A F U. S ) ) | 
						
							| 21 | 17 20 | syl |  |-  ( S e. T -> ( ( z e. _V |-> ( A F z ) ) ` U. S ) = ( A F U. S ) ) | 
						
							| 22 | 21 | 3ad2ant1 |  |-  ( ( S e. T /\ S C_ On /\ S =/= (/) ) -> ( ( z e. _V |-> ( A F z ) ) ` U. S ) = ( A F U. S ) ) | 
						
							| 23 | 11 | a1i |  |-  ( x e. S -> ( ( z e. _V |-> ( A F z ) ) ` x ) = ( A F x ) ) | 
						
							| 24 | 23 | iuneq2i |  |-  U_ x e. S ( ( z e. _V |-> ( A F z ) ) ` x ) = U_ x e. S ( A F x ) | 
						
							| 25 | 24 | a1i |  |-  ( ( S e. T /\ S C_ On /\ S =/= (/) ) -> U_ x e. S ( ( z e. _V |-> ( A F z ) ) ` x ) = U_ x e. S ( A F x ) ) | 
						
							| 26 | 16 22 25 | 3eqtr3d |  |-  ( ( S e. T /\ S C_ On /\ S =/= (/) ) -> ( A F U. S ) = U_ x e. S ( A F x ) ) |