| Step | Hyp | Ref | Expression | 
						
							| 1 |  | fveq2 |  |-  ( z = (/) -> ( rec ( F , I ) ` z ) = ( rec ( F , I ) ` (/) ) ) | 
						
							| 2 |  | fveq2 |  |-  ( z = (/) -> ( rec ( F , (/) ) ` z ) = ( rec ( F , (/) ) ` (/) ) ) | 
						
							| 3 | 1 2 | eqeq12d |  |-  ( z = (/) -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> ( rec ( F , I ) ` (/) ) = ( rec ( F , (/) ) ` (/) ) ) ) | 
						
							| 4 | 3 | imbi2d |  |-  ( z = (/) -> ( ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) <-> ( -. I e. _V -> ( rec ( F , I ) ` (/) ) = ( rec ( F , (/) ) ` (/) ) ) ) ) | 
						
							| 5 |  | fveq2 |  |-  ( z = y -> ( rec ( F , I ) ` z ) = ( rec ( F , I ) ` y ) ) | 
						
							| 6 |  | fveq2 |  |-  ( z = y -> ( rec ( F , (/) ) ` z ) = ( rec ( F , (/) ) ` y ) ) | 
						
							| 7 | 5 6 | eqeq12d |  |-  ( z = y -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 8 | 7 | imbi2d |  |-  ( z = y -> ( ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) <-> ( -. I e. _V -> ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) ) | 
						
							| 9 |  | fveq2 |  |-  ( z = suc y -> ( rec ( F , I ) ` z ) = ( rec ( F , I ) ` suc y ) ) | 
						
							| 10 |  | fveq2 |  |-  ( z = suc y -> ( rec ( F , (/) ) ` z ) = ( rec ( F , (/) ) ` suc y ) ) | 
						
							| 11 | 9 10 | eqeq12d |  |-  ( z = suc y -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> ( rec ( F , I ) ` suc y ) = ( rec ( F , (/) ) ` suc y ) ) ) | 
						
							| 12 | 11 | imbi2d |  |-  ( z = suc y -> ( ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) <-> ( -. I e. _V -> ( rec ( F , I ) ` suc y ) = ( rec ( F , (/) ) ` suc y ) ) ) ) | 
						
							| 13 |  | fveq2 |  |-  ( z = x -> ( rec ( F , I ) ` z ) = ( rec ( F , I ) ` x ) ) | 
						
							| 14 |  | fveq2 |  |-  ( z = x -> ( rec ( F , (/) ) ` z ) = ( rec ( F , (/) ) ` x ) ) | 
						
							| 15 | 13 14 | eqeq12d |  |-  ( z = x -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) ) | 
						
							| 16 | 15 | imbi2d |  |-  ( z = x -> ( ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) <-> ( -. I e. _V -> ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) ) ) | 
						
							| 17 |  | rdgprc0 |  |-  ( -. I e. _V -> ( rec ( F , I ) ` (/) ) = (/) ) | 
						
							| 18 |  | 0ex |  |-  (/) e. _V | 
						
							| 19 | 18 | rdg0 |  |-  ( rec ( F , (/) ) ` (/) ) = (/) | 
						
							| 20 | 17 19 | eqtr4di |  |-  ( -. I e. _V -> ( rec ( F , I ) ` (/) ) = ( rec ( F , (/) ) ` (/) ) ) | 
						
							| 21 |  | fveq2 |  |-  ( ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) -> ( F ` ( rec ( F , I ) ` y ) ) = ( F ` ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 22 |  | rdgsuc |  |-  ( y e. On -> ( rec ( F , I ) ` suc y ) = ( F ` ( rec ( F , I ) ` y ) ) ) | 
						
							| 23 |  | rdgsuc |  |-  ( y e. On -> ( rec ( F , (/) ) ` suc y ) = ( F ` ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 24 | 22 23 | eqeq12d |  |-  ( y e. On -> ( ( rec ( F , I ) ` suc y ) = ( rec ( F , (/) ) ` suc y ) <-> ( F ` ( rec ( F , I ) ` y ) ) = ( F ` ( rec ( F , (/) ) ` y ) ) ) ) | 
						
							| 25 | 21 24 | imbitrrid |  |-  ( y e. On -> ( ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) -> ( rec ( F , I ) ` suc y ) = ( rec ( F , (/) ) ` suc y ) ) ) | 
						
							| 26 | 25 | imim2d |  |-  ( y e. On -> ( ( -. I e. _V -> ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) -> ( -. I e. _V -> ( rec ( F , I ) ` suc y ) = ( rec ( F , (/) ) ` suc y ) ) ) ) | 
						
							| 27 |  | r19.21v |  |-  ( A. y e. z ( -. I e. _V -> ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) <-> ( -. I e. _V -> A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 28 |  | limord |  |-  ( Lim z -> Ord z ) | 
						
							| 29 |  | ordsson |  |-  ( Ord z -> z C_ On ) | 
						
							| 30 |  | rdgfnon |  |-  rec ( F , I ) Fn On | 
						
							| 31 |  | rdgfnon |  |-  rec ( F , (/) ) Fn On | 
						
							| 32 |  | fvreseq |  |-  ( ( ( rec ( F , I ) Fn On /\ rec ( F , (/) ) Fn On ) /\ z C_ On ) -> ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) <-> A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 33 | 30 31 32 | mpanl12 |  |-  ( z C_ On -> ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) <-> A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 34 | 28 29 33 | 3syl |  |-  ( Lim z -> ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) <-> A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) ) | 
						
							| 35 |  | rneq |  |-  ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) -> ran ( rec ( F , I ) |` z ) = ran ( rec ( F , (/) ) |` z ) ) | 
						
							| 36 |  | df-ima |  |-  ( rec ( F , I ) " z ) = ran ( rec ( F , I ) |` z ) | 
						
							| 37 |  | df-ima |  |-  ( rec ( F , (/) ) " z ) = ran ( rec ( F , (/) ) |` z ) | 
						
							| 38 | 35 36 37 | 3eqtr4g |  |-  ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) -> ( rec ( F , I ) " z ) = ( rec ( F , (/) ) " z ) ) | 
						
							| 39 | 38 | unieqd |  |-  ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) -> U. ( rec ( F , I ) " z ) = U. ( rec ( F , (/) ) " z ) ) | 
						
							| 40 |  | vex |  |-  z e. _V | 
						
							| 41 |  | rdglim |  |-  ( ( z e. _V /\ Lim z ) -> ( rec ( F , I ) ` z ) = U. ( rec ( F , I ) " z ) ) | 
						
							| 42 |  | rdglim |  |-  ( ( z e. _V /\ Lim z ) -> ( rec ( F , (/) ) ` z ) = U. ( rec ( F , (/) ) " z ) ) | 
						
							| 43 | 41 42 | eqeq12d |  |-  ( ( z e. _V /\ Lim z ) -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> U. ( rec ( F , I ) " z ) = U. ( rec ( F , (/) ) " z ) ) ) | 
						
							| 44 | 40 43 | mpan |  |-  ( Lim z -> ( ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) <-> U. ( rec ( F , I ) " z ) = U. ( rec ( F , (/) ) " z ) ) ) | 
						
							| 45 | 39 44 | imbitrrid |  |-  ( Lim z -> ( ( rec ( F , I ) |` z ) = ( rec ( F , (/) ) |` z ) -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) ) | 
						
							| 46 | 34 45 | sylbird |  |-  ( Lim z -> ( A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) ) | 
						
							| 47 | 46 | imim2d |  |-  ( Lim z -> ( ( -. I e. _V -> A. y e. z ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) -> ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) ) ) | 
						
							| 48 | 27 47 | biimtrid |  |-  ( Lim z -> ( A. y e. z ( -. I e. _V -> ( rec ( F , I ) ` y ) = ( rec ( F , (/) ) ` y ) ) -> ( -. I e. _V -> ( rec ( F , I ) ` z ) = ( rec ( F , (/) ) ` z ) ) ) ) | 
						
							| 49 | 4 8 12 16 20 26 48 | tfinds |  |-  ( x e. On -> ( -. I e. _V -> ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) ) | 
						
							| 50 | 49 | com12 |  |-  ( -. I e. _V -> ( x e. On -> ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) ) | 
						
							| 51 | 50 | ralrimiv |  |-  ( -. I e. _V -> A. x e. On ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) | 
						
							| 52 |  | eqfnfv |  |-  ( ( rec ( F , I ) Fn On /\ rec ( F , (/) ) Fn On ) -> ( rec ( F , I ) = rec ( F , (/) ) <-> A. x e. On ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) ) | 
						
							| 53 | 30 31 52 | mp2an |  |-  ( rec ( F , I ) = rec ( F , (/) ) <-> A. x e. On ( rec ( F , I ) ` x ) = ( rec ( F , (/) ) ` x ) ) | 
						
							| 54 | 51 53 | sylibr |  |-  ( -. I e. _V -> rec ( F , I ) = rec ( F , (/) ) ) |