| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sseq2 |  |-  ( A = B -> ( x C_ A <-> x C_ B ) ) | 
						
							| 2 | 1 | 3ad2ant2 |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( x C_ A <-> x C_ B ) ) | 
						
							| 3 |  | predeq1 |  |-  ( R = S -> Pred ( R , A , y ) = Pred ( S , A , y ) ) | 
						
							| 4 |  | predeq2 |  |-  ( A = B -> Pred ( S , A , y ) = Pred ( S , B , y ) ) | 
						
							| 5 | 3 4 | sylan9eq |  |-  ( ( R = S /\ A = B ) -> Pred ( R , A , y ) = Pred ( S , B , y ) ) | 
						
							| 6 | 5 | 3adant3 |  |-  ( ( R = S /\ A = B /\ F = G ) -> Pred ( R , A , y ) = Pred ( S , B , y ) ) | 
						
							| 7 | 6 | sseq1d |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( Pred ( R , A , y ) C_ x <-> Pred ( S , B , y ) C_ x ) ) | 
						
							| 8 | 7 | ralbidv |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( A. y e. x Pred ( R , A , y ) C_ x <-> A. y e. x Pred ( S , B , y ) C_ x ) ) | 
						
							| 9 | 2 8 | anbi12d |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) <-> ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) ) ) | 
						
							| 10 |  | simp3 |  |-  ( ( R = S /\ A = B /\ F = G ) -> F = G ) | 
						
							| 11 | 5 | reseq2d |  |-  ( ( R = S /\ A = B ) -> ( f |` Pred ( R , A , y ) ) = ( f |` Pred ( S , B , y ) ) ) | 
						
							| 12 | 11 | 3adant3 |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( f |` Pred ( R , A , y ) ) = ( f |` Pred ( S , B , y ) ) ) | 
						
							| 13 | 10 12 | fveq12d |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( F ` ( f |` Pred ( R , A , y ) ) ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) | 
						
							| 14 | 13 | eqeq2d |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) <-> ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) ) | 
						
							| 15 | 14 | ralbidv |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) <-> A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) ) | 
						
							| 16 | 9 15 | 3anbi23d |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( ( f Fn x /\ ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) ) <-> ( f Fn x /\ ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) ) ) | 
						
							| 17 | 16 | exbidv |  |-  ( ( R = S /\ A = B /\ F = G ) -> ( E. x ( f Fn x /\ ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) ) <-> E. x ( f Fn x /\ ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) ) ) | 
						
							| 18 | 17 | abbidv |  |-  ( ( R = S /\ A = B /\ F = G ) -> { f | E. x ( f Fn x /\ ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) ) } = { f | E. x ( f Fn x /\ ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) } ) | 
						
							| 19 | 18 | unieqd |  |-  ( ( R = S /\ A = B /\ F = G ) -> U. { f | E. x ( f Fn x /\ ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) ) } = U. { f | E. x ( f Fn x /\ ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) } ) | 
						
							| 20 |  | dfwrecsOLD |  |-  wrecs ( R , A , F ) = U. { f | E. x ( f Fn x /\ ( x C_ A /\ A. y e. x Pred ( R , A , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( F ` ( f |` Pred ( R , A , y ) ) ) ) } | 
						
							| 21 |  | dfwrecsOLD |  |-  wrecs ( S , B , G ) = U. { f | E. x ( f Fn x /\ ( x C_ B /\ A. y e. x Pred ( S , B , y ) C_ x ) /\ A. y e. x ( f ` y ) = ( G ` ( f |` Pred ( S , B , y ) ) ) ) } | 
						
							| 22 | 19 20 21 | 3eqtr4g |  |-  ( ( R = S /\ A = B /\ F = G ) -> wrecs ( R , A , F ) = wrecs ( S , B , G ) ) |