| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rrxtopnfi.1 |  |-  ( ph -> I e. Fin ) | 
						
							| 2 | 1 | rrxtopn |  |-  ( ph -> ( TopOpen ` ( RR^ ` I ) ) = ( MetOpen ` ( f e. ( Base ` ( RR^ ` I ) ) , g e. ( Base ` ( RR^ ` I ) ) |-> ( sqrt ` ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 3 |  | eqid |  |-  ( RR^ ` I ) = ( RR^ ` I ) | 
						
							| 4 |  | eqid |  |-  ( Base ` ( RR^ ` I ) ) = ( Base ` ( RR^ ` I ) ) | 
						
							| 5 | 1 3 4 | rrxbasefi |  |-  ( ph -> ( Base ` ( RR^ ` I ) ) = ( RR ^m I ) ) | 
						
							| 6 | 5 | adantr |  |-  ( ( ph /\ f e. ( Base ` ( RR^ ` I ) ) ) -> ( Base ` ( RR^ ` I ) ) = ( RR ^m I ) ) | 
						
							| 7 |  | simpl |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> ph ) | 
						
							| 8 |  | simprl |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> f e. ( Base ` ( RR^ ` I ) ) ) | 
						
							| 9 |  | simpr |  |-  ( ( ph /\ f e. ( Base ` ( RR^ ` I ) ) ) -> f e. ( Base ` ( RR^ ` I ) ) ) | 
						
							| 10 | 9 6 | eleqtrd |  |-  ( ( ph /\ f e. ( Base ` ( RR^ ` I ) ) ) -> f e. ( RR ^m I ) ) | 
						
							| 11 | 8 10 | syldan |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> f e. ( RR ^m I ) ) | 
						
							| 12 |  | simprr |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> g e. ( Base ` ( RR^ ` I ) ) ) | 
						
							| 13 |  | simpr |  |-  ( ( ph /\ g e. ( Base ` ( RR^ ` I ) ) ) -> g e. ( Base ` ( RR^ ` I ) ) ) | 
						
							| 14 | 5 | adantr |  |-  ( ( ph /\ g e. ( Base ` ( RR^ ` I ) ) ) -> ( Base ` ( RR^ ` I ) ) = ( RR ^m I ) ) | 
						
							| 15 | 13 14 | eleqtrd |  |-  ( ( ph /\ g e. ( Base ` ( RR^ ` I ) ) ) -> g e. ( RR ^m I ) ) | 
						
							| 16 | 12 15 | syldan |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> g e. ( RR ^m I ) ) | 
						
							| 17 |  | elmapi |  |-  ( f e. ( RR ^m I ) -> f : I --> RR ) | 
						
							| 18 | 17 | adantr |  |-  ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> f : I --> RR ) | 
						
							| 19 | 18 | ffvelcdmda |  |-  ( ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( f ` x ) e. RR ) | 
						
							| 20 |  | elmapi |  |-  ( g e. ( RR ^m I ) -> g : I --> RR ) | 
						
							| 21 | 20 | adantl |  |-  ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> g : I --> RR ) | 
						
							| 22 | 21 | ffvelcdmda |  |-  ( ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( g ` x ) e. RR ) | 
						
							| 23 | 19 22 | resubcld |  |-  ( ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( ( f ` x ) - ( g ` x ) ) e. RR ) | 
						
							| 24 | 23 | resqcld |  |-  ( ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) e. RR ) | 
						
							| 25 |  | eqid |  |-  ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) = ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) | 
						
							| 26 | 24 25 | fmptd |  |-  ( ( f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) : I --> RR ) | 
						
							| 27 | 26 | 3adant1 |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) : I --> RR ) | 
						
							| 28 | 1 | 3ad2ant1 |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> I e. Fin ) | 
						
							| 29 |  | 0red |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> 0 e. RR ) | 
						
							| 30 | 27 28 29 | fidmfisupp |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) finSupp 0 ) | 
						
							| 31 |  | regsumsupp |  |-  ( ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) : I --> RR /\ ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) finSupp 0 /\ I e. Fin ) -> ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) = sum_ k e. ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) supp 0 ) ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) ) | 
						
							| 32 | 27 30 28 31 | syl3anc |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) = sum_ k e. ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) supp 0 ) ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) ) | 
						
							| 33 |  | ax-resscn |  |-  RR C_ CC | 
						
							| 34 | 33 | a1i |  |-  ( f e. ( RR ^m I ) -> RR C_ CC ) | 
						
							| 35 | 17 34 | fssd |  |-  ( f e. ( RR ^m I ) -> f : I --> CC ) | 
						
							| 36 | 35 | 3ad2ant2 |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> f : I --> CC ) | 
						
							| 37 | 36 | ffvelcdmda |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( f ` x ) e. CC ) | 
						
							| 38 | 33 | a1i |  |-  ( g e. ( RR ^m I ) -> RR C_ CC ) | 
						
							| 39 | 20 38 | fssd |  |-  ( g e. ( RR ^m I ) -> g : I --> CC ) | 
						
							| 40 | 39 | 3ad2ant3 |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> g : I --> CC ) | 
						
							| 41 | 40 | ffvelcdmda |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( g ` x ) e. CC ) | 
						
							| 42 | 37 41 | subcld |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( ( f ` x ) - ( g ` x ) ) e. CC ) | 
						
							| 43 | 42 | sqcld |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ x e. I ) -> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) e. CC ) | 
						
							| 44 | 43 25 | fmptd |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) : I --> CC ) | 
						
							| 45 | 28 44 | fsumsupp0 |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> sum_ k e. ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) supp 0 ) ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) = sum_ k e. I ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) ) | 
						
							| 46 |  | eqidd |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ k e. I ) -> ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) = ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) | 
						
							| 47 |  | fveq2 |  |-  ( x = k -> ( f ` x ) = ( f ` k ) ) | 
						
							| 48 |  | fveq2 |  |-  ( x = k -> ( g ` x ) = ( g ` k ) ) | 
						
							| 49 | 47 48 | oveq12d |  |-  ( x = k -> ( ( f ` x ) - ( g ` x ) ) = ( ( f ` k ) - ( g ` k ) ) ) | 
						
							| 50 | 49 | oveq1d |  |-  ( x = k -> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) = ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) | 
						
							| 51 | 50 | adantl |  |-  ( ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ k e. I ) /\ x = k ) -> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) = ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) | 
						
							| 52 |  | simpr |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ k e. I ) -> k e. I ) | 
						
							| 53 |  | ovexd |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ k e. I ) -> ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) e. _V ) | 
						
							| 54 | 46 51 52 53 | fvmptd |  |-  ( ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) /\ k e. I ) -> ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) = ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) | 
						
							| 55 | 54 | sumeq2dv |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> sum_ k e. I ( ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ` k ) = sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) | 
						
							| 56 | 32 45 55 | 3eqtrd |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) = sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) | 
						
							| 57 | 56 | fveq2d |  |-  ( ( ph /\ f e. ( RR ^m I ) /\ g e. ( RR ^m I ) ) -> ( sqrt ` ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) ) = ( sqrt ` sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) ) | 
						
							| 58 | 7 11 16 57 | syl3anc |  |-  ( ( ph /\ ( f e. ( Base ` ( RR^ ` I ) ) /\ g e. ( Base ` ( RR^ ` I ) ) ) ) -> ( sqrt ` ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) ) = ( sqrt ` sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) ) | 
						
							| 59 | 5 6 58 | mpoeq123dva |  |-  ( ph -> ( f e. ( Base ` ( RR^ ` I ) ) , g e. ( Base ` ( RR^ ` I ) ) |-> ( sqrt ` ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) ) ) = ( f e. ( RR ^m I ) , g e. ( RR ^m I ) |-> ( sqrt ` sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) ) ) | 
						
							| 60 | 59 | fveq2d |  |-  ( ph -> ( MetOpen ` ( f e. ( Base ` ( RR^ ` I ) ) , g e. ( Base ` ( RR^ ` I ) ) |-> ( sqrt ` ( RRfld gsum ( x e. I |-> ( ( ( f ` x ) - ( g ` x ) ) ^ 2 ) ) ) ) ) ) = ( MetOpen ` ( f e. ( RR ^m I ) , g e. ( RR ^m I ) |-> ( sqrt ` sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) ) ) ) | 
						
							| 61 | 2 60 | eqtrd |  |-  ( ph -> ( TopOpen ` ( RR^ ` I ) ) = ( MetOpen ` ( f e. ( RR ^m I ) , g e. ( RR ^m I ) |-> ( sqrt ` sum_ k e. I ( ( ( f ` k ) - ( g ` k ) ) ^ 2 ) ) ) ) ) |