| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-rim |  |-  RingIso = ( r e. _V , s e. _V |-> { f e. ( r RingHom s ) | `' f e. ( s RingHom r ) } ) | 
						
							| 2 | 1 | a1i |  |-  ( ( R e. V /\ S e. W ) -> RingIso = ( r e. _V , s e. _V |-> { f e. ( r RingHom s ) | `' f e. ( s RingHom r ) } ) ) | 
						
							| 3 |  | oveq12 |  |-  ( ( r = R /\ s = S ) -> ( r RingHom s ) = ( R RingHom S ) ) | 
						
							| 4 | 3 | adantl |  |-  ( ( ( R e. V /\ S e. W ) /\ ( r = R /\ s = S ) ) -> ( r RingHom s ) = ( R RingHom S ) ) | 
						
							| 5 |  | oveq12 |  |-  ( ( s = S /\ r = R ) -> ( s RingHom r ) = ( S RingHom R ) ) | 
						
							| 6 | 5 | ancoms |  |-  ( ( r = R /\ s = S ) -> ( s RingHom r ) = ( S RingHom R ) ) | 
						
							| 7 | 6 | adantl |  |-  ( ( ( R e. V /\ S e. W ) /\ ( r = R /\ s = S ) ) -> ( s RingHom r ) = ( S RingHom R ) ) | 
						
							| 8 | 7 | eleq2d |  |-  ( ( ( R e. V /\ S e. W ) /\ ( r = R /\ s = S ) ) -> ( `' f e. ( s RingHom r ) <-> `' f e. ( S RingHom R ) ) ) | 
						
							| 9 | 4 8 | rabeqbidv |  |-  ( ( ( R e. V /\ S e. W ) /\ ( r = R /\ s = S ) ) -> { f e. ( r RingHom s ) | `' f e. ( s RingHom r ) } = { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } ) | 
						
							| 10 |  | elex |  |-  ( R e. V -> R e. _V ) | 
						
							| 11 | 10 | adantr |  |-  ( ( R e. V /\ S e. W ) -> R e. _V ) | 
						
							| 12 |  | elex |  |-  ( S e. W -> S e. _V ) | 
						
							| 13 | 12 | adantl |  |-  ( ( R e. V /\ S e. W ) -> S e. _V ) | 
						
							| 14 |  | ovex |  |-  ( R RingHom S ) e. _V | 
						
							| 15 | 14 | rabex |  |-  { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } e. _V | 
						
							| 16 | 15 | a1i |  |-  ( ( R e. V /\ S e. W ) -> { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } e. _V ) | 
						
							| 17 | 2 9 11 13 16 | ovmpod |  |-  ( ( R e. V /\ S e. W ) -> ( R RingIso S ) = { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } ) | 
						
							| 18 | 17 | eleq2d |  |-  ( ( R e. V /\ S e. W ) -> ( F e. ( R RingIso S ) <-> F e. { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } ) ) | 
						
							| 19 |  | cnveq |  |-  ( f = F -> `' f = `' F ) | 
						
							| 20 | 19 | eleq1d |  |-  ( f = F -> ( `' f e. ( S RingHom R ) <-> `' F e. ( S RingHom R ) ) ) | 
						
							| 21 | 20 | elrab |  |-  ( F e. { f e. ( R RingHom S ) | `' f e. ( S RingHom R ) } <-> ( F e. ( R RingHom S ) /\ `' F e. ( S RingHom R ) ) ) | 
						
							| 22 | 18 21 | bitrdi |  |-  ( ( R e. V /\ S e. W ) -> ( F e. ( R RingIso S ) <-> ( F e. ( R RingHom S ) /\ `' F e. ( S RingHom R ) ) ) ) |