| Step | Hyp | Ref | Expression | 
						
							| 1 |  | coiun |  |-  ( `' ( 2nd |` ( _V X. _V ) ) o. U_ y e. B ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) = U_ y e. B ( `' ( 2nd |` ( _V X. _V ) ) o. ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) | 
						
							| 2 |  | inss1 |  |-  ( dom G i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ dom G | 
						
							| 3 |  | fndm |  |-  ( G Fn B -> dom G = B ) | 
						
							| 4 | 2 3 | sseqtrid |  |-  ( G Fn B -> ( dom G i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ B ) | 
						
							| 5 |  | dfco2a |  |-  ( ( dom G i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ B -> ( G o. ( 2nd |` ( _V X. _V ) ) ) = U_ y e. B ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) | 
						
							| 6 | 4 5 | syl |  |-  ( G Fn B -> ( G o. ( 2nd |` ( _V X. _V ) ) ) = U_ y e. B ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) | 
						
							| 7 | 6 | coeq2d |  |-  ( G Fn B -> ( `' ( 2nd |` ( _V X. _V ) ) o. ( G o. ( 2nd |` ( _V X. _V ) ) ) ) = ( `' ( 2nd |` ( _V X. _V ) ) o. U_ y e. B ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) ) | 
						
							| 8 |  | inss1 |  |-  ( dom ( { ( G ` y ) } X. ( _V X. { y } ) ) i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ dom ( { ( G ` y ) } X. ( _V X. { y } ) ) | 
						
							| 9 |  | dmxpss |  |-  dom ( { ( G ` y ) } X. ( _V X. { y } ) ) C_ { ( G ` y ) } | 
						
							| 10 | 8 9 | sstri |  |-  ( dom ( { ( G ` y ) } X. ( _V X. { y } ) ) i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ { ( G ` y ) } | 
						
							| 11 |  | dfco2a |  |-  ( ( dom ( { ( G ` y ) } X. ( _V X. { y } ) ) i^i ran ( 2nd |` ( _V X. _V ) ) ) C_ { ( G ` y ) } -> ( ( { ( G ` y ) } X. ( _V X. { y } ) ) o. ( 2nd |` ( _V X. _V ) ) ) = U_ x e. { ( G ` y ) } ( ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) X. ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) ) ) | 
						
							| 12 | 10 11 | ax-mp |  |-  ( ( { ( G ` y ) } X. ( _V X. { y } ) ) o. ( 2nd |` ( _V X. _V ) ) ) = U_ x e. { ( G ` y ) } ( ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) X. ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) ) | 
						
							| 13 |  | fvex |  |-  ( G ` y ) e. _V | 
						
							| 14 |  | fparlem2 |  |-  ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) = ( _V X. { x } ) | 
						
							| 15 |  | sneq |  |-  ( x = ( G ` y ) -> { x } = { ( G ` y ) } ) | 
						
							| 16 | 15 | xpeq2d |  |-  ( x = ( G ` y ) -> ( _V X. { x } ) = ( _V X. { ( G ` y ) } ) ) | 
						
							| 17 | 14 16 | eqtrid |  |-  ( x = ( G ` y ) -> ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) = ( _V X. { ( G ` y ) } ) ) | 
						
							| 18 | 15 | imaeq2d |  |-  ( x = ( G ` y ) -> ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) = ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { ( G ` y ) } ) ) | 
						
							| 19 |  | df-ima |  |-  ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { ( G ` y ) } ) = ran ( ( { ( G ` y ) } X. ( _V X. { y } ) ) |` { ( G ` y ) } ) | 
						
							| 20 |  | ssid |  |-  { ( G ` y ) } C_ { ( G ` y ) } | 
						
							| 21 |  | xpssres |  |-  ( { ( G ` y ) } C_ { ( G ` y ) } -> ( ( { ( G ` y ) } X. ( _V X. { y } ) ) |` { ( G ` y ) } ) = ( { ( G ` y ) } X. ( _V X. { y } ) ) ) | 
						
							| 22 | 20 21 | ax-mp |  |-  ( ( { ( G ` y ) } X. ( _V X. { y } ) ) |` { ( G ` y ) } ) = ( { ( G ` y ) } X. ( _V X. { y } ) ) | 
						
							| 23 | 22 | rneqi |  |-  ran ( ( { ( G ` y ) } X. ( _V X. { y } ) ) |` { ( G ` y ) } ) = ran ( { ( G ` y ) } X. ( _V X. { y } ) ) | 
						
							| 24 | 13 | snnz |  |-  { ( G ` y ) } =/= (/) | 
						
							| 25 |  | rnxp |  |-  ( { ( G ` y ) } =/= (/) -> ran ( { ( G ` y ) } X. ( _V X. { y } ) ) = ( _V X. { y } ) ) | 
						
							| 26 | 24 25 | ax-mp |  |-  ran ( { ( G ` y ) } X. ( _V X. { y } ) ) = ( _V X. { y } ) | 
						
							| 27 | 23 26 | eqtri |  |-  ran ( ( { ( G ` y ) } X. ( _V X. { y } ) ) |` { ( G ` y ) } ) = ( _V X. { y } ) | 
						
							| 28 | 19 27 | eqtri |  |-  ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { ( G ` y ) } ) = ( _V X. { y } ) | 
						
							| 29 | 18 28 | eqtrdi |  |-  ( x = ( G ` y ) -> ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) = ( _V X. { y } ) ) | 
						
							| 30 | 17 29 | xpeq12d |  |-  ( x = ( G ` y ) -> ( ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) X. ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) ) = ( ( _V X. { ( G ` y ) } ) X. ( _V X. { y } ) ) ) | 
						
							| 31 | 13 30 | iunxsn |  |-  U_ x e. { ( G ` y ) } ( ( `' ( 2nd |` ( _V X. _V ) ) " { x } ) X. ( ( { ( G ` y ) } X. ( _V X. { y } ) ) " { x } ) ) = ( ( _V X. { ( G ` y ) } ) X. ( _V X. { y } ) ) | 
						
							| 32 | 12 31 | eqtri |  |-  ( ( { ( G ` y ) } X. ( _V X. { y } ) ) o. ( 2nd |` ( _V X. _V ) ) ) = ( ( _V X. { ( G ` y ) } ) X. ( _V X. { y } ) ) | 
						
							| 33 | 32 | cnveqi |  |-  `' ( ( { ( G ` y ) } X. ( _V X. { y } ) ) o. ( 2nd |` ( _V X. _V ) ) ) = `' ( ( _V X. { ( G ` y ) } ) X. ( _V X. { y } ) ) | 
						
							| 34 |  | cnvco |  |-  `' ( ( { ( G ` y ) } X. ( _V X. { y } ) ) o. ( 2nd |` ( _V X. _V ) ) ) = ( `' ( 2nd |` ( _V X. _V ) ) o. `' ( { ( G ` y ) } X. ( _V X. { y } ) ) ) | 
						
							| 35 |  | cnvxp |  |-  `' ( ( _V X. { ( G ` y ) } ) X. ( _V X. { y } ) ) = ( ( _V X. { y } ) X. ( _V X. { ( G ` y ) } ) ) | 
						
							| 36 | 33 34 35 | 3eqtr3i |  |-  ( `' ( 2nd |` ( _V X. _V ) ) o. `' ( { ( G ` y ) } X. ( _V X. { y } ) ) ) = ( ( _V X. { y } ) X. ( _V X. { ( G ` y ) } ) ) | 
						
							| 37 |  | fparlem2 |  |-  ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) = ( _V X. { y } ) | 
						
							| 38 | 37 | xpeq2i |  |-  ( { ( G ` y ) } X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) = ( { ( G ` y ) } X. ( _V X. { y } ) ) | 
						
							| 39 |  | fnsnfv |  |-  ( ( G Fn B /\ y e. B ) -> { ( G ` y ) } = ( G " { y } ) ) | 
						
							| 40 | 39 | xpeq1d |  |-  ( ( G Fn B /\ y e. B ) -> ( { ( G ` y ) } X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) = ( ( G " { y } ) X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) ) | 
						
							| 41 | 38 40 | eqtr3id |  |-  ( ( G Fn B /\ y e. B ) -> ( { ( G ` y ) } X. ( _V X. { y } ) ) = ( ( G " { y } ) X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) ) | 
						
							| 42 | 41 | cnveqd |  |-  ( ( G Fn B /\ y e. B ) -> `' ( { ( G ` y ) } X. ( _V X. { y } ) ) = `' ( ( G " { y } ) X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) ) | 
						
							| 43 |  | cnvxp |  |-  `' ( ( G " { y } ) X. ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) ) = ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) | 
						
							| 44 | 42 43 | eqtrdi |  |-  ( ( G Fn B /\ y e. B ) -> `' ( { ( G ` y ) } X. ( _V X. { y } ) ) = ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) | 
						
							| 45 | 44 | coeq2d |  |-  ( ( G Fn B /\ y e. B ) -> ( `' ( 2nd |` ( _V X. _V ) ) o. `' ( { ( G ` y ) } X. ( _V X. { y } ) ) ) = ( `' ( 2nd |` ( _V X. _V ) ) o. ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) ) | 
						
							| 46 | 36 45 | eqtr3id |  |-  ( ( G Fn B /\ y e. B ) -> ( ( _V X. { y } ) X. ( _V X. { ( G ` y ) } ) ) = ( `' ( 2nd |` ( _V X. _V ) ) o. ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) ) | 
						
							| 47 | 46 | iuneq2dv |  |-  ( G Fn B -> U_ y e. B ( ( _V X. { y } ) X. ( _V X. { ( G ` y ) } ) ) = U_ y e. B ( `' ( 2nd |` ( _V X. _V ) ) o. ( ( `' ( 2nd |` ( _V X. _V ) ) " { y } ) X. ( G " { y } ) ) ) ) | 
						
							| 48 | 1 7 47 | 3eqtr4a |  |-  ( G Fn B -> ( `' ( 2nd |` ( _V X. _V ) ) o. ( G o. ( 2nd |` ( _V X. _V ) ) ) ) = U_ y e. B ( ( _V X. { y } ) X. ( _V X. { ( G ` y ) } ) ) ) |