| Step | Hyp | Ref | Expression | 
						
							| 1 |  | setsms.x |  |-  ( ph -> X = ( Base ` M ) ) | 
						
							| 2 |  | setsms.d |  |-  ( ph -> D = ( ( dist ` M ) |` ( X X. X ) ) ) | 
						
							| 3 |  | setsms.k |  |-  ( ph -> K = ( M sSet <. ( TopSet ` ndx ) , ( MetOpen ` D ) >. ) ) | 
						
							| 4 |  | baseid |  |-  Base = Slot ( Base ` ndx ) | 
						
							| 5 |  | 1re |  |-  1 e. RR | 
						
							| 6 |  | 1lt9 |  |-  1 < 9 | 
						
							| 7 | 5 6 | ltneii |  |-  1 =/= 9 | 
						
							| 8 |  | basendx |  |-  ( Base ` ndx ) = 1 | 
						
							| 9 |  | tsetndx |  |-  ( TopSet ` ndx ) = 9 | 
						
							| 10 | 8 9 | neeq12i |  |-  ( ( Base ` ndx ) =/= ( TopSet ` ndx ) <-> 1 =/= 9 ) | 
						
							| 11 | 7 10 | mpbir |  |-  ( Base ` ndx ) =/= ( TopSet ` ndx ) | 
						
							| 12 | 4 11 | setsnid |  |-  ( Base ` M ) = ( Base ` ( M sSet <. ( TopSet ` ndx ) , ( MetOpen ` D ) >. ) ) | 
						
							| 13 | 3 | fveq2d |  |-  ( ph -> ( Base ` K ) = ( Base ` ( M sSet <. ( TopSet ` ndx ) , ( MetOpen ` D ) >. ) ) ) | 
						
							| 14 | 12 1 13 | 3eqtr4a |  |-  ( ph -> X = ( Base ` K ) ) |