:: BHSP_6 semantic presentation

definition
let c1 be RealUnitarySpace;
assume E1: ( the add of c1 is commutative & the add of c1 is associative & the add of c1 is has_a_unity ) ;
let c2 be finite Subset of c1;
func setsum a2 -> Element of a1 means :E1: :: BHSP_6:def 1
ex b1 being FinSequence of the carrier of a1 st
( b1 is one-to-one & rng b1 = a2 & a3 = the add of a1 "**" b1 );
existence
ex b1 being Element of c1ex b2 being FinSequence of the carrier of c1 st
( b2 is one-to-one & rng b2 = c2 & b1 = the add of c1 "**" b2 )
proof
consider c3 being FinSequence such that
E2: rng c3 = c2
and E3: c3 is one-to-one by FINSEQ_4:73;
reconsider c4 = c3 as FinSequence of the carrier of c1 by E2, FINSEQ_1:def 4;
ex b1 being FinSequence of the carrier of c1 st
( b1 is one-to-one & rng b1 = c2 & the add of c1 "**" c4 = the add of c1 "**" b1 ) by E2, E3;
hence ex b1 being Element of c1ex b2 being FinSequence of the carrier of c1 st
( b2 is one-to-one & rng b2 = c2 & b1 = the add of c1 "**" b2 ) ;
end;
uniqueness
for b1, b2 being Element of c1 holds
( ( ) implies ( for b3 being FinSequence of the carrier of c1 holds
not ( b3 is one-to-one & rng b3 = c2 & b1 = the add of c1 "**" b3 ) or for b3 being FinSequence of the carrier of c1 holds
not ( b3 is one-to-one & rng b3 = c2 & b2 = the add of c1 "**" b3 ) or b1 = b2 ) )
proof
let c3, c4 be Element of c1;
assume that E2: ex b1 being FinSequence of the carrier of c1 st
( b1 is one-to-one & rng b1 = c2 & c3 = the add of c1 "**" b1 )
and E3: ex b1 being FinSequence of the carrier of c1 st
( b1 is one-to-one & rng b1 = c2 & c4 = the add of c1 "**" b1 ) ;
consider c5 being FinSequence of the carrier of c1 such that
E4: c5 is one-to-one
and E5: rng c5 = c2
and E6: c3 = the add of c1 "**" c5 by E2;
consider c6 being FinSequence of the carrier of c1 such that
E7: c6 is one-to-one
and E8: rng c6 = c2
and E9: c4 = the add of c1 "**" c6 by E3;
( dom c5 = dom c6 & ex b1 being Permutation of dom c5 st
( c6 = c5 * b1 & dom b1 = dom c5 & rng b1 = dom c5 ) ) by E4, E5, E7, E8, BHSP_5:1;
then consider c7 being Permutation of dom c5 such that
E10: c6 = c5 * c7 ;
thus c3 = c4 by E1, E6, E9, E10, FINSOP_1:8;
end;
end;

:: deftheorem E1 defines setsum BHSP_6:def 1 :
for b1 being RealUnitarySpace holds
( ( the add of b1 is commutative & the add of b1 is associative & the add of b1 is has_a_unity ) implies ( for b2 being finite Subset of b1
for b3 being Element of b1 holds
( b3 = setsum b2 iff ex b4 being FinSequence of the carrier of b1 st
( b4 is one-to-one & rng b4 = b2 & b3 = the add of b1 "**" b4 ) ) ) );

theorem E2: :: BHSP_6:1
for b1 being RealUnitarySpace holds
( ( the add of b1 is commutative & the add of b1 is associative & the add of b1 is has_a_unity ) implies ( for b2 being finite Subset of b1
for b3 being Function of the carrier of b1,the carrier of b1 holds
( ( b2 c= dom b3 & for b4 being set holds
( b4 in dom b3 implies b3 . b4 = b4 ) ) implies ( setsum b2 = setopfunc b2,the carrier of b1,the carrier of b1,b3,the add of b1 ) ) ) )
proof
let c1 be RealUnitarySpace;
assume E3: ( the add of c1 is commutative & the add of c1 is associative & the add of c1 is has_a_unity ) ;
let c2 be finite Subset of c1;
let c3 be Function of the carrier of c1,the carrier of c1;
assume E4: ( c2 c= dom c3 & for b1 being set holds
( b1 in dom c3 implies c3 . b1 = b1 ) ) ;
consider c4 being FinSequence of the carrier of c1 such that
E5: ( c4 is one-to-one & rng c4 = c2 & setsum c2 = the add of c1 "**" c4 ) by E3, E1;
E6: dom (Func_Seq c3,c4) = dom c4
proof
now
let c5 be set ;
E7: ( c5 in dom (Func_Seq c3,c4) iff c5 in dom (c3 * c4) ) by BHSP_5:def 4;
( c5 in dom c4 implies c4 . c5 in rng c4 ) by FUNCT_1:12;
hence ( c5 in dom (Func_Seq c3,c4) iff c5 in dom c4 ) by E4, E5, E7, FUNCT_1:21;
end;
hence dom (Func_Seq c3,c4) = dom c4 by TARSKI:2;
end;
now
let c5 be set ;
assume E7: c5 in dom (Func_Seq c3,c4) ;
dom (Func_Seq c3,c4) is Subset of NAT by RELSET_1:12;
then reconsider c6 = c5 as Nat by E7;
E8: c4 . c6 in rng c4 by E6, E7, FUNCT_1:12;
(Func_Seq c3,c4) . c5 = (c3 * c4) . c6 by BHSP_5:def 4
.= c3 . (c4 . c6) by E6, E7, FUNCT_1:23
.= c4 . c6 by E4, E5, E8 ;
hence (Func_Seq c3,c4) . c5 = c4 . c5 ;
end;
then Func_Seq c3,c4 = c4 by E6, FUNCT_1:9;
hence setsum c2 = setopfunc c2,the carrier of c1,the carrier of c1,c3,the add of c1 by E3, E4, E5, BHSP_5:def 5;
end;

theorem E3: :: BHSP_6:2
for b1 being RealUnitarySpace holds
( ( the add of b1 is commutative & the add of b1 is associative & the add of b1 is has_a_unity ) implies ( for b2, b3 being finite Subset of b1 holds
( b2 misses b3 implies for b4 being finite Subset of b1 holds
( b4 = b2 \/ b3 implies setsum b4 = (setsum b2) + (setsum b3) ) ) ) )
proof
let c1 be RealUnitarySpace;
assume E4: ( the add of c1 is commutative & the add of c1 is associative & the add of c1 is has_a_unity ) ;
let c2, c3 be finite Subset of c1;
assume E5: c2 misses c3 ;
let c4 be finite Subset of c1;
assume E6: c4 = c2 \/ c3 ;
reconsider c5 = id the carrier of c1 as Function of the carrier of c1,the carrier of c1 ;
E7: for b1 being set holds
( b1 in the carrier of c1 implies c5 . b1 = b1 ) by FUNCT_1:35;
E8: dom c5 = the carrier of c1 by FUNCT_2:def 1;
then E9: setsum c2 = setopfunc c2,the carrier of c1,the carrier of c1,c5,the add of c1 by E4, E7, E2;
E10: setsum c3 = setopfunc c3,the carrier of c1,the carrier of c1,c5,the add of c1 by E4, E7, E8, E2;
setopfunc c4,the carrier of c1,the carrier of c1,c5,the add of c1 = the add of c1 . (setopfunc c2,the carrier of c1,the carrier of c1,c5,the add of c1),(setopfunc c3,the carrier of c1,the carrier of c1,c5,the add of c1) by E4, E5, E6, E8, BHSP_5:14
.= (setopfunc c2,the carrier of c1,the carrier of c1,c5,the add of c1) + (setopfunc c3,the carrier of c1,the carrier of c1,c5,the add of c1) by RLVECT_1:5 ;
hence setsum c4 = (setsum c2) + (setsum c3) by E4, E7, E8, E9, E10, E2;
end;

definition
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
attr a2 is summable_set means :E4: :: BHSP_6:def 2
ex b1 being Point of a1 st
for b2 being Real holds
not ( b2 > 0 & for b3 being finite Subset of a1 holds
not ( not b3 is empty & b3 c= a2 & for b4 being finite Subset of a1 holds
not ( b3 c= b4 & b4 c= a2 & not ||.(b1 - (setsum b4)).|| < b2 ) ) );
end;

:: deftheorem E4 defines summable_set BHSP_6:def 2 :
for b1 being RealUnitarySpace
for b2 being Subset of b1 holds
( b2 is summable_set iff ex b3 being Point of b1 st
for b4 being Real holds
not ( b4 > 0 & for b5 being finite Subset of b1 holds
not ( not b5 is empty & b5 c= b2 & for b6 being finite Subset of b1 holds
not ( b5 c= b6 & b6 c= b2 & not ||.(b3 - (setsum b6)).|| < b4 ) ) ) );

definition
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
assume E5: c2 is summable_set ;
func sum a2 -> Point of a1 means :: BHSP_6:def 3
for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of a1 holds
not ( not b2 is empty & b2 c= a2 & for b3 being finite Subset of a1 holds
not ( b2 c= b3 & b3 c= a2 & not ||.(a3 - (setsum b3)).|| < b1 ) ) );
existence
ex b1 being Point of c1 st
for b2 being Real holds
not ( b2 > 0 & for b3 being finite Subset of c1 holds
not ( not b3 is empty & b3 c= c2 & for b4 being finite Subset of c1 holds
not ( b3 c= b4 & b4 c= c2 & not ||.(b1 - (setsum b4)).|| < b2 ) ) )
by E5, E4;
uniqueness
for b1, b2 being Point of c1 holds
( ( for b3 being Real holds
not ( b3 > 0 & for b4 being finite Subset of c1 holds
not ( not b4 is empty & b4 c= c2 & for b5 being finite Subset of c1 holds
not ( b4 c= b5 & b5 c= c2 & not ||.(b1 - (setsum b5)).|| < b3 ) ) ) & for b3 being Real holds
not ( b3 > 0 & for b4 being finite Subset of c1 holds
not ( not b4 is empty & b4 c= c2 & for b5 being finite Subset of c1 holds
not ( b4 c= b5 & b5 c= c2 & not ||.(b2 - (setsum b5)).|| < b3 ) ) ) ) implies ( b1 = b2 ) )
proof
let c3, c4 be Point of c1;
assume that E6: for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not ||.(c3 - (setsum b3)).|| < b1 ) ) )
and E7: for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not ||.(c4 - (setsum b3)).|| < b1 ) ) ) ;
E8: now
let c5 be Real;
assume E9: c5 > 0 ;
set c6 = c5 / 2;
E10: ( c5 / 2 is Real & c5 / 2 > 0 ) by E9, REAL_2:127;
E11: (c5 / 2) + (c5 / 2) = c5 ;
consider c7 being finite Subset of c1 such that
E12: ( not c7 is empty & c7 c= c2 & for b1 being finite Subset of c1 holds
not ( c7 c= b1 & b1 c= c2 & not ||.(c3 - (setsum b1)).|| < c5 / 2 ) ) by E6, E10;
consider c8 being finite Subset of c1 such that
E13: ( not c8 is empty & c8 c= c2 & for b1 being finite Subset of c1 holds
not ( c8 c= b1 & b1 c= c2 & not ||.(c4 - (setsum b1)).|| < c5 / 2 ) ) by E7, E10;
set c9 = c7 \/ c8;
E14: c7 \/ c8 c= c2 by E12, E13, XBOOLE_1:8;
( c7 \/ c8 is finite Subset of c1 & c7 c= c7 \/ c8 ) by XBOOLE_1:7;
then E15: ||.(c3 - (setsum (c7 \/ c8))).|| < c5 / 2 by E12, E14;
( c7 \/ c8 is finite Subset of c1 & c8 c= c7 \/ c8 ) by XBOOLE_1:7;
then ||.(c4 - (setsum (c7 \/ c8))).|| < c5 / 2 by E13, E14;
then ||.(- (c4 - (setsum (c7 \/ c8)))).|| < c5 / 2 by BHSP_1:37;
then E16: ||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).|| < c5 by E11, E15, XREAL_1:10;
||.((c3 - (setsum (c7 \/ c8))) + (- (c4 - (setsum (c7 \/ c8))))).|| <= ||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).|| by BHSP_1:36;
then ||.((c3 - (setsum (c7 \/ c8))) + (- (c4 - (setsum (c7 \/ c8))))).|| + (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||) < (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||) + c5 by E16, XREAL_1:10;
then E17: (||.((c3 - (setsum (c7 \/ c8))) + (- (c4 - (setsum (c7 \/ c8))))).|| + (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||)) + (- (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||)) < (c5 + (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||)) + (- (||.(c3 - (setsum (c7 \/ c8))).|| + ||.(- (c4 - (setsum (c7 \/ c8)))).||)) by XREAL_1:10;
||.(c3 - c4).|| = ||.((c3 - c4) + (0. c1)).|| by RLVECT_1:def 7
.= ||.((c3 - c4) + ((setsum (c7 \/ c8)) + (- (setsum (c7 \/ c8))))).|| by RLVECT_1:16
.= ||.((c3 - c4) + ((setsum (c7 \/ c8)) - (setsum (c7 \/ c8)))).|| by RLVECT_1:def 11
.= ||.(((c3 - c4) + (setsum (c7 \/ c8))) - (setsum (c7 \/ c8))).|| by RLVECT_1:42
.= ||.((c3 - (c4 - (setsum (c7 \/ c8)))) - (setsum (c7 \/ c8))).|| by RLVECT_1:43
.= ||.(c3 - ((setsum (c7 \/ c8)) + (c4 - (setsum (c7 \/ c8))))).|| by RLVECT_1:41
.= ||.((c3 - (setsum (c7 \/ c8))) - (c4 - (setsum (c7 \/ c8)))).|| by RLVECT_1:41
.= ||.((c3 - (setsum (c7 \/ c8))) + (- (c4 - (setsum (c7 \/ c8))))).|| by RLVECT_1:def 11 ;
hence ||.(c3 - c4).|| < c5 by E17;
end;
c3 = c4
proof
assume c3 <> c4 ;
then c3 - c4 <> 0. c1 by VECTSP_1:66;
then E9: ||.(c3 - c4).|| <> 0 by BHSP_1:32;
0 <= ||.(c3 - c4).|| by BHSP_1:34;
hence not verum by E8, E9;
end;
hence c3 = c4 ;
end;
end;

:: deftheorem defines sum BHSP_6:def 3 :
for b1 being RealUnitarySpace
for b2 being Subset of b1 holds
( b2 is summable_set implies for b3 being Point of b1 holds
( b3 = sum b2 iff for b4 being Real holds
not ( b4 > 0 & for b5 being finite Subset of b1 holds
not ( not b5 is empty & b5 c= b2 & for b6 being finite Subset of b1 holds
not ( b5 c= b6 & b6 c= b2 & not ||.(b3 - (setsum b6)).|| < b4 ) ) ) ) );

definition
let c1 be RealUnitarySpace;
let c2 be linear-Functional of c1;
attr a2 is Bounded means :E5: :: BHSP_6:def 4
ex b1 being Real st
( b1 > 0 & for b2 being Point of a1 holds abs (a2 . b2) <= b1 * ||.b2.|| );
end;

:: deftheorem E5 defines Bounded BHSP_6:def 4 :
for b1 being RealUnitarySpace
for b2 being linear-Functional of b1 holds
( b2 is Bounded iff ex b3 being Real st
( b3 > 0 & for b4 being Point of b1 holds abs (b2 . b4) <= b3 * ||.b4.|| ) );

definition
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
attr a2 is weakly_summable_set means :E6: :: BHSP_6:def 5
ex b1 being Point of a1 st
for b2 being linear-Functional of a1 holds
( b2 is Bounded implies for b3 being Real holds
not ( b3 > 0 & for b4 being finite Subset of a1 holds
not ( not b4 is empty & b4 c= a2 & for b5 being finite Subset of a1 holds
not ( b4 c= b5 & b5 c= a2 & not abs (b2 . (b1 - (setsum b5))) < b3 ) ) ) );
end;

:: deftheorem E6 defines weakly_summable_set BHSP_6:def 5 :
for b1 being RealUnitarySpace
for b2 being Subset of b1 holds
( b2 is weakly_summable_set iff ex b3 being Point of b1 st
for b4 being linear-Functional of b1 holds
( b4 is Bounded implies for b5 being Real holds
not ( b5 > 0 & for b6 being finite Subset of b1 holds
not ( not b6 is empty & b6 c= b2 & for b7 being finite Subset of b1 holds
not ( b6 c= b7 & b7 c= b2 & not abs (b4 . (b3 - (setsum b7))) < b5 ) ) ) ) );

definition
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
let c3 be Functional of c1;
pred a2 is_summable_set_by a3 means :E7: :: BHSP_6:def 6
ex b1 being Real st
for b2 being Real holds
not ( b2 > 0 & for b3 being finite Subset of a1 holds
not ( not b3 is empty & b3 c= a2 & for b4 being finite Subset of a1 holds
not ( b3 c= b4 & b4 c= a2 & not abs (b1 - (setopfunc b4,the carrier of a1,REAL ,a3,addreal )) < b2 ) ) );
end;

:: deftheorem E7 defines is_summable_set_by BHSP_6:def 6 :
for b1 being RealUnitarySpace
for b2 being Subset of b1
for b3 being Functional of b1 holds
( b2 is_summable_set_by b3 iff ex b4 being Real st
for b5 being Real holds
not ( b5 > 0 & for b6 being finite Subset of b1 holds
not ( not b6 is empty & b6 c= b2 & for b7 being finite Subset of b1 holds
not ( b6 c= b7 & b7 c= b2 & not abs (b4 - (setopfunc b7,the carrier of b1,REAL ,b3,addreal )) < b5 ) ) ) );

definition
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
let c3 be Functional of c1;
assume E8: c2 is_summable_set_by c3 ;
func sum_byfunc a2,a3 -> Real means :: BHSP_6:def 7
for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of a1 holds
not ( not b2 is empty & b2 c= a2 & for b3 being finite Subset of a1 holds
not ( b2 c= b3 & b3 c= a2 & not abs (a4 - (setopfunc b3,the carrier of a1,REAL ,a3,addreal )) < b1 ) ) );
existence
ex b1 being Real st
for b2 being Real holds
not ( b2 > 0 & for b3 being finite Subset of c1 holds
not ( not b3 is empty & b3 c= c2 & for b4 being finite Subset of c1 holds
not ( b3 c= b4 & b4 c= c2 & not abs (b1 - (setopfunc b4,the carrier of c1,REAL ,c3,addreal )) < b2 ) ) )
by E8, E7;
uniqueness
for b1, b2 being Real holds
( ( for b3 being Real holds
not ( b3 > 0 & for b4 being finite Subset of c1 holds
not ( not b4 is empty & b4 c= c2 & for b5 being finite Subset of c1 holds
not ( b4 c= b5 & b5 c= c2 & not abs (b1 - (setopfunc b5,the carrier of c1,REAL ,c3,addreal )) < b3 ) ) ) & for b3 being Real holds
not ( b3 > 0 & for b4 being finite Subset of c1 holds
not ( not b4 is empty & b4 c= c2 & for b5 being finite Subset of c1 holds
not ( b4 c= b5 & b5 c= c2 & not abs (b2 - (setopfunc b5,the carrier of c1,REAL ,c3,addreal )) < b3 ) ) ) ) implies ( b1 = b2 ) )
proof
let c4, c5 be Real;
assume that E9: for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not abs (c4 - (setopfunc b3,the carrier of c1,REAL ,c3,addreal )) < b1 ) ) )
and E10: for b1 being Real holds
not ( b1 > 0 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not abs (c5 - (setopfunc b3,the carrier of c1,REAL ,c3,addreal )) < b1 ) ) ) ;
E11: now
let c6 be real number ;
assume E12: c6 > 0 ;
set c7 = c6 / 2;
E13: ( c6 / 2 is Real & c6 / 2 > 0 ) by E12, REAL_2:127, XREAL_0:def 1;
E14: (c6 / 2) + (c6 / 2) = c6 ;
consider c8 being finite Subset of c1 such that
E15: ( not c8 is empty & c8 c= c2 & for b1 being finite Subset of c1 holds
not ( c8 c= b1 & b1 c= c2 & not abs (c4 - (setopfunc b1,the carrier of c1,REAL ,c3,addreal )) < c6 / 2 ) ) by E9, E13;
consider c9 being finite Subset of c1 such that
E16: ( not c9 is empty & c9 c= c2 & for b1 being finite Subset of c1 holds
not ( c9 c= b1 & b1 c= c2 & not abs (c5 - (setopfunc b1,the carrier of c1,REAL ,c3,addreal )) < c6 / 2 ) ) by E10, E13;
set c10 = c8 \/ c9;
E17: c8 \/ c9 c= c2 by E15, E16, XBOOLE_1:8;
( c8 \/ c9 is finite Subset of c1 & c8 c= c8 \/ c9 ) by XBOOLE_1:7;
then E18: abs (c4 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal )) < c6 / 2 by E15, E17;
( c8 \/ c9 is finite Subset of c1 & c9 c= c8 \/ c9 ) by XBOOLE_1:7;
then E19: abs (c5 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal )) < c6 / 2 by E16, E17;
E20: abs ((c4 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal )) - (c5 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal ))) <= (abs (c4 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal ))) + (abs (c5 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal ))) by COMPLEX1:143;
(abs (c4 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal ))) + (abs (c5 - (setopfunc (c8 \/ c9),the carrier of c1,REAL ,c3,addreal ))) < c6 by E14, E18, E19, XREAL_1:10;
hence abs (c4 - c5) < c6 by E20, XREAL_1:2;
end;
c4 = c5
proof
assume E12: c4 <> c5 ;
E13: abs (c4 - c5) <> 0
proof
assume abs (c4 - c5) = 0 ;
then c4 - c5 = 0 by ABSVALUE:7;
hence not verum by E12;
end;
0 <= abs (c4 - c5) by COMPLEX1:132;
hence not verum by E11, E13;
end;
hence c4 = c5 ;
end;
end;

:: deftheorem defines sum_byfunc BHSP_6:def 7 :
for b1 being RealUnitarySpace
for b2 being Subset of b1
for b3 being Functional of b1 holds
( b2 is_summable_set_by b3 implies for b4 being Real holds
( b4 = sum_byfunc b2,b3 iff for b5 being Real holds
not ( b5 > 0 & for b6 being finite Subset of b1 holds
not ( not b6 is empty & b6 c= b2 & for b7 being finite Subset of b1 holds
not ( b6 c= b7 & b7 c= b2 & not abs (b4 - (setopfunc b7,the carrier of b1,REAL ,b3,addreal )) < b5 ) ) ) ) );

theorem E8: :: BHSP_6:3
for b1 being RealUnitarySpace
for b2 being Subset of b1 holds
( b2 is summable_set implies b2 is weakly_summable_set )
proof
let c1 be RealUnitarySpace;
let c2 be Subset of c1;
assume c2 is summable_set ;
then consider c3 being Point of c1 such that
E9: for b1 being Real holds
not ( 0 < b1 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not ||.(c3 - (setsum b3)).|| < b1 ) ) ) by E4;
now
let c4 be linear-Functional of c1;
assume E10: c4 is Bounded ;
consider c5 being Real such that
E11: ( 0 < c5 & for b1 being Point of c1 holds abs (c4 . b1) <= c5 * ||.b1.|| ) by E10, E5;
now
let c6 be Real;
assume E12: 0 < c6 ;
set c7 = c6 / c5;
E13: 0 < c6 / c5 by E11, E12, REAL_2:127;
E14: (c6 / c5) * c5 = c6 by E11, XCMPLX_1:88;
consider c8 being finite Subset of c1 such that
E15: ( not c8 is empty & c8 c= c2 & for b1 being finite Subset of c1 holds
not ( c8 c= b1 & b1 c= c2 & not ||.(c3 - (setsum b1)).|| < c6 / c5 ) ) by E9, E13;
now
let c9 be finite Subset of c1;
assume E16: ( c8 c= c9 & c9 c= c2 ) ;
||.(c3 - (setsum c9)).|| < c6 / c5 by E15, E16;
then E17: c5 * ||.(c3 - (setsum c9)).|| < c6 by E11, E14, XREAL_1:70;
abs (c4 . (c3 - (setsum c9))) <= c5 * ||.(c3 - (setsum c9)).|| by E11;
then (abs (c4 . (c3 - (setsum c9)))) + (c5 * ||.(c3 - (setsum c9)).||) < (c5 * ||.(c3 - (setsum c9)).||) + c6 by E17, XREAL_1:10;
then ((abs (c4 . (c3 - (setsum c9)))) + (c5 * ||.(c3 - (setsum c9)).||)) - (c5 * ||.(c3 - (setsum c9)).||) < ((c5 * ||.(c3 - (setsum c9)).||) + c6) - (c5 * ||.(c3 - (setsum c9)).||) by REAL_1:92;
hence abs (c4 . (c3 - (setsum c9))) < c6 ;
end;
hence ex b1 being finite Subset of c1 st
( not b1 is empty & b1 c= c2 & for b2 being finite Subset of c1 holds
not ( b1 c= b2 & b2 c= c2 & not abs (c4 . (c3 - (setsum b2))) < c6 ) ) by E15;
end;
hence for b1 being Real holds
not ( 0 < b1 & for b2 being finite Subset of c1 holds
not ( not b2 is empty & b2 c= c2 & for b3 being finite Subset of c1 holds
not ( b2 c= b3 & b3 c= c2 & not abs (c4 . (c3 - (setsum b3))) < b1 ) ) ) ;
end;
hence c2 is weakly_summable_set by E6;
end;

theorem E9: :: BHSP_6:4
for b1 being RealUnitarySpace
for b2 being linear-Functional of b1
for b3 being FinSequence of the carrier of b1 holds
( len b3 >= 1 implies for b4 being FinSequence of REAL holds
( ( dom b3 = dom b4 & for b5 being Nat holds
( b5 in dom b4 implies b4 . b5 = b2 . (b3 . b5) ) ) implies ( b2 . (the add of b1 "**" b3) = addreal "**" b4 ) ) )
proof
let c1 be RealUnitarySpace;
let c2 be linear-Functional of c1;
let c3 be FinSequence of the carrier of c1;
assume E10: len c3 >= 1 ;
let c4 be FinSequence of REAL ;
assume E11: ( dom c3 = dom c4 & for b1 being Nat holds
( b1 in dom c4 implies c4 . b1 = c2 . (c3 . b1) ) ) ;
consider c5 being Function of NAT ,the carrier of c1 such that
E12: c5 . 1 = c3 . 1
and E13: for b1 being Nat holds
( ( ) implies ( not 0 <> b1 or not b1 < len c3 or c5 . (b1 + 1) = the add of c1 . (c5 . b1),(c3 . (b1 + 1)) ) )
and E14: the add of c1 "**" c3 = c5 . (len c3) by E10, FINSOP_1:2;
Seg (len c4) = dom c3 by E11, FINSEQ_1:def 3
.= Seg (len c3) by FINSEQ_1:def 3 ;
then E15: len c4 = len c3 by FINSEQ_1:8;
then consider c6 being Function of NAT , REAL such that
E16: c6 . 1 = c4 . 1
and E17: for b1 being Nat holds
( ( ) implies ( not 0 <> b1 or not b1 < len c4 or c6 . (b1 + 1) = addreal . (c6 . b1),(c4 . (b1 + 1)) ) )
and E18: addreal "**" c4 = c6 . (len c4) by E10, FINSOP_1:2;
defpred S1[ Nat] means ( ( 1 <= a1 & a1 <= len c4 ) implies ( c6 . a1 = c2 . (c5 . a1) ) );
for b1 being Nat holds
S1[b1]
proof
E19: S1[0] ;
E20: now
let c7 be Nat;
assume E21: S1[c7] ;
now
assume E22: ( 1 <= c7 + 1 & c7 + 1 <= len c4 ) ;
E23: c7 <= c7 + 1 by NAT_1:29;
per cases not ( not c7 = 0 & not c7 <> 0 ) ;
suppose E24: c7 = 0 ;
1 in dom c3 by E10, FINSEQ_3:27;
hence c6 . (c7 + 1) = c2 . (c5 . (c7 + 1)) by E11, E12, E16, E24;
end;
suppose E24: c7 <> 0 ;
then 0 < c7 ;
then E25: 0 + 1 <= c7 by INT_1:20;
E26: (c7 + 1) - 1 < (len c4) - 0 by E22, REAL_1:92;
E27: c7 + 1 in dom c4 by E22, FINSEQ_3:27;
reconsider c8 = c5 . c7 as Element of c1 ;
c3 . (c7 + 1) in rng c3 by E11, E27, FUNCT_1:12;
then reconsider c9 = c3 . (c7 + 1) as Element of c1 ;
reconsider c10 = c8 as VECTOR of c1 ;
reconsider c11 = c9 as VECTOR of c1 ;
set c12 = c2 . c10;
set c13 = c2 . c11;
thus c6 . (c7 + 1) = addreal . (c6 . c7),(c4 . (c7 + 1)) by E17, E24, E26
.= addreal . (c2 . (c5 . c7)),(c2 . c9) by E11, E21, E22, E23, E25, E27, XREAL_1:2
.= (c2 . c10) + (c2 . c11) by BINOP_2:def 9
.= c2 . (c10 + c11) by HAHNBAN:def 4
.= c2 . (the add of c1 . (c5 . c7),(c3 . (c7 + 1))) by RLVECT_1:5
.= c2 . (c5 . (c7 + 1)) by E13, E15, E24, E26 ;
end;
end;
end;
hence S1[c7 + 1] ;
end;
thus for b1 being Nat holds
S1[b1] from NAT_1:sch 1(E19, E20);
end;
hence c2 . (the add of c1 "**" c3) = addreal "**" c4 by E10, E14, E15, E18;
end;

theorem E10: :: BHSP_6:5
for b1 being RealUnitarySpace holds
( ( the add of b1 is commutative & the add of b1 is associative & the add of b1 is has_a_unity ) implies ( for b2 being finite Subset of b1 holds
( not b2 is empty implies for b3 being linear-Functional of b1 holds b3 . (setsum b2) = setopfunc b2,the carrier of b1,REAL ,b3,addreal ) ) )
proof
let c1 be RealUnitarySpace;
assume E11: ( the add of c1 is commutative & the add of c1 is associative & the add of c1 is has_a_unity ) ;
let c2 be finite Subset of c1;
assume E12: not c2 is empty ;
let c3 be linear-Functional of c1;
E13: dom c3 = the carrier of c1 by FUNCT_2:def 1;
consider c4 being FinSequence of the carrier of c1 such that
E14: ( c4 is one-to-one & rng c4 = c2 & setsum c2 = the add of c1 "**" c4 ) by E11, E1;
reconsider c5 = Func_Seq c3,c4 as FinSequence of REAL ;
E15: dom (Func_Seq c3,c4) = dom c4
proof
now
let c6 be set ;
E16: ( c6 in dom (Func_Seq c3,c4) iff c6 in dom (c3 * c4) ) by BHSP_5:def 4;
( c6 in dom c4 implies c4 . c6 in rng c4 ) by FUNCT_1:12;
hence ( c6 in dom (Func_Seq c3,c4) iff c6 in dom c4 ) by E13, E16, FUNCT_1:21;
end;
hence dom (