| Step | Hyp | Ref | Expression | 
						
							| 1 |  | exidres.1 |  |-  X = ran G | 
						
							| 2 |  | exidres.2 |  |-  U = ( GId ` G ) | 
						
							| 3 |  | exidres.3 |  |-  H = ( G |` ( Y X. Y ) ) | 
						
							| 4 | 3 | dmeqi |  |-  dom H = dom ( G |` ( Y X. Y ) ) | 
						
							| 5 |  | xpss12 |  |-  ( ( Y C_ X /\ Y C_ X ) -> ( Y X. Y ) C_ ( X X. X ) ) | 
						
							| 6 | 5 | anidms |  |-  ( Y C_ X -> ( Y X. Y ) C_ ( X X. X ) ) | 
						
							| 7 | 1 | opidon2OLD |  |-  ( G e. ( Magma i^i ExId ) -> G : ( X X. X ) -onto-> X ) | 
						
							| 8 |  | fof |  |-  ( G : ( X X. X ) -onto-> X -> G : ( X X. X ) --> X ) | 
						
							| 9 |  | fdm |  |-  ( G : ( X X. X ) --> X -> dom G = ( X X. X ) ) | 
						
							| 10 | 7 8 9 | 3syl |  |-  ( G e. ( Magma i^i ExId ) -> dom G = ( X X. X ) ) | 
						
							| 11 | 10 | sseq2d |  |-  ( G e. ( Magma i^i ExId ) -> ( ( Y X. Y ) C_ dom G <-> ( Y X. Y ) C_ ( X X. X ) ) ) | 
						
							| 12 | 6 11 | imbitrrid |  |-  ( G e. ( Magma i^i ExId ) -> ( Y C_ X -> ( Y X. Y ) C_ dom G ) ) | 
						
							| 13 | 12 | imp |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> ( Y X. Y ) C_ dom G ) | 
						
							| 14 |  | ssdmres |  |-  ( ( Y X. Y ) C_ dom G <-> dom ( G |` ( Y X. Y ) ) = ( Y X. Y ) ) | 
						
							| 15 | 13 14 | sylib |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> dom ( G |` ( Y X. Y ) ) = ( Y X. Y ) ) | 
						
							| 16 | 4 15 | eqtrid |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> dom H = ( Y X. Y ) ) | 
						
							| 17 | 16 | dmeqd |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> dom dom H = dom ( Y X. Y ) ) | 
						
							| 18 |  | dmxpid |  |-  dom ( Y X. Y ) = Y | 
						
							| 19 | 17 18 | eqtrdi |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> dom dom H = Y ) | 
						
							| 20 | 19 | eleq2d |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) -> ( U e. dom dom H <-> U e. Y ) ) | 
						
							| 21 | 20 | biimp3ar |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> U e. dom dom H ) | 
						
							| 22 |  | ssel2 |  |-  ( ( Y C_ X /\ x e. Y ) -> x e. X ) | 
						
							| 23 | 1 2 | cmpidelt |  |-  ( ( G e. ( Magma i^i ExId ) /\ x e. X ) -> ( ( U G x ) = x /\ ( x G U ) = x ) ) | 
						
							| 24 | 22 23 | sylan2 |  |-  ( ( G e. ( Magma i^i ExId ) /\ ( Y C_ X /\ x e. Y ) ) -> ( ( U G x ) = x /\ ( x G U ) = x ) ) | 
						
							| 25 | 24 | anassrs |  |-  ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ x e. Y ) -> ( ( U G x ) = x /\ ( x G U ) = x ) ) | 
						
							| 26 | 25 | adantrl |  |-  ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ ( U e. Y /\ x e. Y ) ) -> ( ( U G x ) = x /\ ( x G U ) = x ) ) | 
						
							| 27 | 3 | oveqi |  |-  ( U H x ) = ( U ( G |` ( Y X. Y ) ) x ) | 
						
							| 28 |  | ovres |  |-  ( ( U e. Y /\ x e. Y ) -> ( U ( G |` ( Y X. Y ) ) x ) = ( U G x ) ) | 
						
							| 29 | 27 28 | eqtrid |  |-  ( ( U e. Y /\ x e. Y ) -> ( U H x ) = ( U G x ) ) | 
						
							| 30 | 29 | eqeq1d |  |-  ( ( U e. Y /\ x e. Y ) -> ( ( U H x ) = x <-> ( U G x ) = x ) ) | 
						
							| 31 | 3 | oveqi |  |-  ( x H U ) = ( x ( G |` ( Y X. Y ) ) U ) | 
						
							| 32 |  | ovres |  |-  ( ( x e. Y /\ U e. Y ) -> ( x ( G |` ( Y X. Y ) ) U ) = ( x G U ) ) | 
						
							| 33 | 31 32 | eqtrid |  |-  ( ( x e. Y /\ U e. Y ) -> ( x H U ) = ( x G U ) ) | 
						
							| 34 | 33 | ancoms |  |-  ( ( U e. Y /\ x e. Y ) -> ( x H U ) = ( x G U ) ) | 
						
							| 35 | 34 | eqeq1d |  |-  ( ( U e. Y /\ x e. Y ) -> ( ( x H U ) = x <-> ( x G U ) = x ) ) | 
						
							| 36 | 30 35 | anbi12d |  |-  ( ( U e. Y /\ x e. Y ) -> ( ( ( U H x ) = x /\ ( x H U ) = x ) <-> ( ( U G x ) = x /\ ( x G U ) = x ) ) ) | 
						
							| 37 | 36 | adantl |  |-  ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ ( U e. Y /\ x e. Y ) ) -> ( ( ( U H x ) = x /\ ( x H U ) = x ) <-> ( ( U G x ) = x /\ ( x G U ) = x ) ) ) | 
						
							| 38 | 26 37 | mpbird |  |-  ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ ( U e. Y /\ x e. Y ) ) -> ( ( U H x ) = x /\ ( x H U ) = x ) ) | 
						
							| 39 | 38 | anassrs |  |-  ( ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ U e. Y ) /\ x e. Y ) -> ( ( U H x ) = x /\ ( x H U ) = x ) ) | 
						
							| 40 | 39 | ralrimiva |  |-  ( ( ( G e. ( Magma i^i ExId ) /\ Y C_ X ) /\ U e. Y ) -> A. x e. Y ( ( U H x ) = x /\ ( x H U ) = x ) ) | 
						
							| 41 | 40 | 3impa |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> A. x e. Y ( ( U H x ) = x /\ ( x H U ) = x ) ) | 
						
							| 42 | 13 | 3adant3 |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> ( Y X. Y ) C_ dom G ) | 
						
							| 43 | 42 14 | sylib |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> dom ( G |` ( Y X. Y ) ) = ( Y X. Y ) ) | 
						
							| 44 | 4 43 | eqtrid |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> dom H = ( Y X. Y ) ) | 
						
							| 45 | 44 | dmeqd |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> dom dom H = dom ( Y X. Y ) ) | 
						
							| 46 | 45 18 | eqtrdi |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> dom dom H = Y ) | 
						
							| 47 | 41 46 | raleqtrrdv |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> A. x e. dom dom H ( ( U H x ) = x /\ ( x H U ) = x ) ) | 
						
							| 48 | 21 47 | jca |  |-  ( ( G e. ( Magma i^i ExId ) /\ Y C_ X /\ U e. Y ) -> ( U e. dom dom H /\ A. x e. dom dom H ( ( U H x ) = x /\ ( x H U ) = x ) ) ) |