| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tngbas.t |  |-  T = ( G toNrmGrp N ) | 
						
							| 2 |  | tngtset.2 |  |-  D = ( dist ` T ) | 
						
							| 3 |  | tngtset.3 |  |-  J = ( MetOpen ` D ) | 
						
							| 4 | 1 2 3 | tngtset |  |-  ( ( G e. V /\ N e. W ) -> J = ( TopSet ` T ) ) | 
						
							| 5 |  | df-mopn |  |-  MetOpen = ( x e. U. ran *Met |-> ( topGen ` ran ( ball ` x ) ) ) | 
						
							| 6 | 5 | dmmptss |  |-  dom MetOpen C_ U. ran *Met | 
						
							| 7 | 6 | sseli |  |-  ( D e. dom MetOpen -> D e. U. ran *Met ) | 
						
							| 8 |  | eqid |  |-  ( -g ` G ) = ( -g ` G ) | 
						
							| 9 | 1 8 | tngds |  |-  ( N e. W -> ( N o. ( -g ` G ) ) = ( dist ` T ) ) | 
						
							| 10 | 9 2 | eqtr4di |  |-  ( N e. W -> ( N o. ( -g ` G ) ) = D ) | 
						
							| 11 | 10 | adantl |  |-  ( ( G e. V /\ N e. W ) -> ( N o. ( -g ` G ) ) = D ) | 
						
							| 12 | 11 | dmeqd |  |-  ( ( G e. V /\ N e. W ) -> dom ( N o. ( -g ` G ) ) = dom D ) | 
						
							| 13 |  | dmcoss |  |-  dom ( N o. ( -g ` G ) ) C_ dom ( -g ` G ) | 
						
							| 14 |  | eqid |  |-  ( Base ` G ) = ( Base ` G ) | 
						
							| 15 |  | eqid |  |-  ( +g ` G ) = ( +g ` G ) | 
						
							| 16 |  | eqid |  |-  ( invg ` G ) = ( invg ` G ) | 
						
							| 17 | 14 15 16 8 | grpsubfval |  |-  ( -g ` G ) = ( x e. ( Base ` G ) , y e. ( Base ` G ) |-> ( x ( +g ` G ) ( ( invg ` G ) ` y ) ) ) | 
						
							| 18 |  | ovex |  |-  ( x ( +g ` G ) ( ( invg ` G ) ` y ) ) e. _V | 
						
							| 19 | 17 18 | dmmpo |  |-  dom ( -g ` G ) = ( ( Base ` G ) X. ( Base ` G ) ) | 
						
							| 20 | 13 19 | sseqtri |  |-  dom ( N o. ( -g ` G ) ) C_ ( ( Base ` G ) X. ( Base ` G ) ) | 
						
							| 21 | 12 20 | eqsstrrdi |  |-  ( ( G e. V /\ N e. W ) -> dom D C_ ( ( Base ` G ) X. ( Base ` G ) ) ) | 
						
							| 22 | 21 | adantr |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> dom D C_ ( ( Base ` G ) X. ( Base ` G ) ) ) | 
						
							| 23 |  | dmss |  |-  ( dom D C_ ( ( Base ` G ) X. ( Base ` G ) ) -> dom dom D C_ dom ( ( Base ` G ) X. ( Base ` G ) ) ) | 
						
							| 24 | 22 23 | syl |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> dom dom D C_ dom ( ( Base ` G ) X. ( Base ` G ) ) ) | 
						
							| 25 |  | dmxpid |  |-  dom ( ( Base ` G ) X. ( Base ` G ) ) = ( Base ` G ) | 
						
							| 26 | 24 25 | sseqtrdi |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> dom dom D C_ ( Base ` G ) ) | 
						
							| 27 |  | simpr |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> D e. U. ran *Met ) | 
						
							| 28 |  | xmetunirn |  |-  ( D e. U. ran *Met <-> D e. ( *Met ` dom dom D ) ) | 
						
							| 29 | 27 28 | sylib |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> D e. ( *Met ` dom dom D ) ) | 
						
							| 30 |  | eqid |  |-  ( MetOpen ` D ) = ( MetOpen ` D ) | 
						
							| 31 | 30 | mopnuni |  |-  ( D e. ( *Met ` dom dom D ) -> dom dom D = U. ( MetOpen ` D ) ) | 
						
							| 32 | 29 31 | syl |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> dom dom D = U. ( MetOpen ` D ) ) | 
						
							| 33 | 1 14 | tngbas |  |-  ( N e. W -> ( Base ` G ) = ( Base ` T ) ) | 
						
							| 34 | 33 | ad2antlr |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> ( Base ` G ) = ( Base ` T ) ) | 
						
							| 35 | 26 32 34 | 3sstr3d |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> U. ( MetOpen ` D ) C_ ( Base ` T ) ) | 
						
							| 36 |  | sspwuni |  |-  ( ( MetOpen ` D ) C_ ~P ( Base ` T ) <-> U. ( MetOpen ` D ) C_ ( Base ` T ) ) | 
						
							| 37 | 35 36 | sylibr |  |-  ( ( ( G e. V /\ N e. W ) /\ D e. U. ran *Met ) -> ( MetOpen ` D ) C_ ~P ( Base ` T ) ) | 
						
							| 38 | 37 | ex |  |-  ( ( G e. V /\ N e. W ) -> ( D e. U. ran *Met -> ( MetOpen ` D ) C_ ~P ( Base ` T ) ) ) | 
						
							| 39 | 7 38 | syl5 |  |-  ( ( G e. V /\ N e. W ) -> ( D e. dom MetOpen -> ( MetOpen ` D ) C_ ~P ( Base ` T ) ) ) | 
						
							| 40 |  | ndmfv |  |-  ( -. D e. dom MetOpen -> ( MetOpen ` D ) = (/) ) | 
						
							| 41 |  | 0ss |  |-  (/) C_ ~P ( Base ` T ) | 
						
							| 42 | 40 41 | eqsstrdi |  |-  ( -. D e. dom MetOpen -> ( MetOpen ` D ) C_ ~P ( Base ` T ) ) | 
						
							| 43 | 39 42 | pm2.61d1 |  |-  ( ( G e. V /\ N e. W ) -> ( MetOpen ` D ) C_ ~P ( Base ` T ) ) | 
						
							| 44 | 3 43 | eqsstrid |  |-  ( ( G e. V /\ N e. W ) -> J C_ ~P ( Base ` T ) ) | 
						
							| 45 | 4 44 | eqsstrrd |  |-  ( ( G e. V /\ N e. W ) -> ( TopSet ` T ) C_ ~P ( Base ` T ) ) | 
						
							| 46 |  | eqid |  |-  ( Base ` T ) = ( Base ` T ) | 
						
							| 47 |  | eqid |  |-  ( TopSet ` T ) = ( TopSet ` T ) | 
						
							| 48 | 46 47 | topnid |  |-  ( ( TopSet ` T ) C_ ~P ( Base ` T ) -> ( TopSet ` T ) = ( TopOpen ` T ) ) | 
						
							| 49 | 45 48 | syl |  |-  ( ( G e. V /\ N e. W ) -> ( TopSet ` T ) = ( TopOpen ` T ) ) | 
						
							| 50 | 4 49 | eqtrd |  |-  ( ( G e. V /\ N e. W ) -> J = ( TopOpen ` T ) ) |