:: LOPBAN_4 semantic presentation

definition
let c1 be non empty Normed_AlgebraStr ;
let c2, c3 be Element of c1;
pred c2,c3 are_commutative means :Def1: :: LOPBAN_4:def 1
a2 * a3 = a3 * a2;
symmetry
for b1, b2 being Element of c1 st b1 * b2 = b2 * b1 holds
b2 * b1 = b1 * b2
;
end;

:: deftheorem Def1 defines are_commutative LOPBAN_4:def 1 :
for b1 being non empty Normed_AlgebraStr
for b2, b3 being Element of b1 holds
( b2,b3 are_commutative iff b2 * b3 = b3 * b2 );

Lemma2: for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being Nat holds
( b2 * (b2 #N b3) = b2 #N (b3 + 1) & (b2 #N b3) * b2 = b2 #N (b3 + 1) & b2 * (b2 #N b3) = (b2 #N b3) * b2 )
proof end;

Lemma3: for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being Element of b1 st b3,b4 are_commutative holds
( b4 * (b3 #N b2) = (b3 #N b2) * b4 & b3 * (b4 #N b2) = (b4 #N b2) * b3 )
proof end;

theorem Th1: :: LOPBAN_4:1
for b1 being Banach_Algebra
for b2, b3 being sequence of b1 st b2 is convergent & b3 is convergent & lim (b2 - b3) = 0. b1 holds
lim b2 = lim b3
proof end;

theorem Th2: :: LOPBAN_4:2
for b1 being Banach_Algebra
for b2 being sequence of b1
for b3 being Element of b1 st ( for b4 being Nat holds b2 . b4 = b3 ) holds
lim b2 = b3
proof end;

theorem Th3: :: LOPBAN_4:3
for b1 being Banach_Algebra
for b2, b3 being sequence of b1 st b2 is convergent & b3 is convergent holds
b2 * b3 is convergent
proof end;

theorem Th4: :: LOPBAN_4:4
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 st b3 is convergent holds
b2 * b3 is convergent
proof end;

theorem Th5: :: LOPBAN_4:5
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 st b3 is convergent holds
b3 * b2 is convergent
proof end;

theorem Th6: :: LOPBAN_4:6
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 st b3 is convergent holds
lim (b2 * b3) = b2 * (lim b3)
proof end;

theorem Th7: :: LOPBAN_4:7
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 st b3 is convergent holds
lim (b3 * b2) = (lim b3) * b2
proof end;

theorem Th8: :: LOPBAN_4:8
for b1 being Banach_Algebra
for b2, b3 being sequence of b1 st b2 is convergent & b3 is convergent holds
lim (b2 * b3) = (lim b2) * (lim b3)
proof end;

theorem Th9: :: LOPBAN_4:9
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 holds
( Partial_Sums (b2 * b3) = b2 * (Partial_Sums b3) & Partial_Sums (b3 * b2) = (Partial_Sums b3) * b2 )
proof end;

theorem Th10: :: LOPBAN_4:10
for b1 being Banach_Algebra
for b2 being Nat
for b3 being sequence of b1 holds ||.((Partial_Sums b3) . b2).|| <= (Partial_Sums ||.b3.||) . b2
proof end;

theorem Th11: :: LOPBAN_4:11
for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being sequence of b1 st ( for b5 being Nat st b5 <= b2 holds
b3 . b5 = b4 . b5 ) holds
(Partial_Sums b3) . b2 = (Partial_Sums b4) . b2
proof end;

theorem Th12: :: LOPBAN_4:12
for b1 being Banach_Algebra
for b2 being sequence of b1
for b3 being Real_Sequence st ( for b4 being Nat holds ||.(b2 . b4).|| <= b3 . b4 ) & b3 is convergent & lim b3 = 0 holds
( b2 is convergent & lim b2 = 0. b1 )
proof end;

definition
let c1 be Banach_Algebra;
let c2 be Element of c1;
func c2 ExpSeq -> sequence of a1 means :Def2: :: LOPBAN_4:def 2
for b1 being Nat holds a3 . b1 = (1 / (b1 ! )) * (a2 #N b1);
existence
ex b1 being sequence of c1 st
for b2 being Nat holds b1 . b2 = (1 / (b2 ! )) * (c2 #N b2)
proof end;
uniqueness
for b1, b2 being sequence of c1 st ( for b3 being Nat holds b1 . b3 = (1 / (b3 ! )) * (c2 #N b3) ) & ( for b3 being Nat holds b2 . b3 = (1 / (b3 ! )) * (c2 #N b3) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def2 defines ExpSeq LOPBAN_4:def 2 :
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being sequence of b1 holds
( b3 = b2 ExpSeq iff for b4 being Nat holds b3 . b4 = (1 / (b4 ! )) * (b2 #N b4) );

scheme :: LOPBAN_4:sch 1
s1{ F1() -> non empty Banach_Algebra, F2( Nat, Nat) -> Point of F1() } :
for b1 being Nat ex b2 being sequence of F1() st
for b3 being Nat holds
( ( b3 <= b1 implies b2 . b3 = F2(b1,b3) ) & ( b3 > b1 implies b2 . b3 = 0. F1() ) )
proof end;

theorem Th13: :: LOPBAN_4:13
( ( for b1 being Nat st 0 < b1 holds
((b1 -' 1) ! ) * b1 = b1 ! ) & ( for b1, b2 being Nat st b2 <= b1 holds
((b1 -' b2) ! ) * ((b1 + 1) - b2) = ((b1 + 1) -' b2) ! ) )
proof end;

definition
let c1 be Nat;
func Coef c1 -> Real_Sequence means :Def3: :: LOPBAN_4:def 3
for b1 being Nat holds
( ( b1 <= a1 implies a2 . b1 = (a1 ! ) / ((b1 ! ) * ((a1 -' b1) ! )) ) & ( b1 > a1 implies a2 . b1 = 0 ) );
existence
ex b1 being Real_Sequence st
for b2 being Nat holds
( ( b2 <= c1 implies b1 . b2 = (c1 ! ) / ((b2 ! ) * ((c1 -' b2) ! )) ) & ( b2 > c1 implies b1 . b2 = 0 ) )
proof end;
uniqueness
for b1, b2 being Real_Sequence st ( for b3 being Nat holds
( ( b3 <= c1 implies b1 . b3 = (c1 ! ) / ((b3 ! ) * ((c1 -' b3) ! )) ) & ( b3 > c1 implies b1 . b3 = 0 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c1 implies b2 . b3 = (c1 ! ) / ((b3 ! ) * ((c1 -' b3) ! )) ) & ( b3 > c1 implies b2 . b3 = 0 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def3 defines Coef LOPBAN_4:def 3 :
for b1 being Nat
for b2 being Real_Sequence holds
( b2 = Coef b1 iff for b3 being Nat holds
( ( b3 <= b1 implies b2 . b3 = (b1 ! ) / ((b3 ! ) * ((b1 -' b3) ! )) ) & ( b3 > b1 implies b2 . b3 = 0 ) ) );

definition
let c1 be Nat;
func Coef_e c1 -> Real_Sequence means :Def4: :: LOPBAN_4:def 4
for b1 being Nat holds
( ( b1 <= a1 implies a2 . b1 = 1 / ((b1 ! ) * ((a1 -' b1) ! )) ) & ( b1 > a1 implies a2 . b1 = 0 ) );
existence
ex b1 being Real_Sequence st
for b2 being Nat holds
( ( b2 <= c1 implies b1 . b2 = 1 / ((b2 ! ) * ((c1 -' b2) ! )) ) & ( b2 > c1 implies b1 . b2 = 0 ) )
proof end;
uniqueness
for b1, b2 being Real_Sequence st ( for b3 being Nat holds
( ( b3 <= c1 implies b1 . b3 = 1 / ((b3 ! ) * ((c1 -' b3) ! )) ) & ( b3 > c1 implies b1 . b3 = 0 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c1 implies b2 . b3 = 1 / ((b3 ! ) * ((c1 -' b3) ! )) ) & ( b3 > c1 implies b2 . b3 = 0 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def4 defines Coef_e LOPBAN_4:def 4 :
for b1 being Nat
for b2 being Real_Sequence holds
( b2 = Coef_e b1 iff for b3 being Nat holds
( ( b3 <= b1 implies b2 . b3 = 1 / ((b3 ! ) * ((b1 -' b3) ! )) ) & ( b3 > b1 implies b2 . b3 = 0 ) ) );

definition
let c1 be Banach_Algebra;
let c2 be sequence of c1;
func Sift c2 -> sequence of a1 means :Def5: :: LOPBAN_4:def 5
( a3 . 0 = 0. a1 & ( for b1 being Nat holds a3 . (b1 + 1) = a2 . b1 ) );
existence
ex b1 being sequence of c1 st
( b1 . 0 = 0. c1 & ( for b2 being Nat holds b1 . (b2 + 1) = c2 . b2 ) )
proof end;
uniqueness
for b1, b2 being sequence of c1 st b1 . 0 = 0. c1 & ( for b3 being Nat holds b1 . (b3 + 1) = c2 . b3 ) & b2 . 0 = 0. c1 & ( for b3 being Nat holds b2 . (b3 + 1) = c2 . b3 ) holds
b1 = b2
proof end;
end;

:: deftheorem Def5 defines Sift LOPBAN_4:def 5 :
for b1 being Banach_Algebra
for b2, b3 being sequence of b1 holds
( b3 = Sift b2 iff ( b3 . 0 = 0. b1 & ( for b4 being Nat holds b3 . (b4 + 1) = b2 . b4 ) ) );

definition
let c1 be Nat;
let c2 be Banach_Algebra;
let c3, c4 be Element of c2;
func Expan c1,c3,c4 -> sequence of a2 means :Def6: :: LOPBAN_4:def 6
for b1 being Nat holds
( ( b1 <= a1 implies a5 . b1 = (((Coef a1) . b1) * (a3 #N b1)) * (a4 #N (a1 -' b1)) ) & ( a1 < b1 implies a5 . b1 = 0. a2 ) );
existence
ex b1 being sequence of c2 st
for b2 being Nat holds
( ( b2 <= c1 implies b1 . b2 = (((Coef c1) . b2) * (c3 #N b2)) * (c4 #N (c1 -' b2)) ) & ( c1 < b2 implies b1 . b2 = 0. c2 ) )
proof end;
uniqueness
for b1, b2 being sequence of c2 st ( for b3 being Nat holds
( ( b3 <= c1 implies b1 . b3 = (((Coef c1) . b3) * (c3 #N b3)) * (c4 #N (c1 -' b3)) ) & ( c1 < b3 implies b1 . b3 = 0. c2 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c1 implies b2 . b3 = (((Coef c1) . b3) * (c3 #N b3)) * (c4 #N (c1 -' b3)) ) & ( c1 < b3 implies b2 . b3 = 0. c2 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def6 defines Expan LOPBAN_4:def 6 :
for b1 being Nat
for b2 being Banach_Algebra
for b3, b4 being Element of b2
for b5 being sequence of b2 holds
( b5 = Expan b1,b3,b4 iff for b6 being Nat holds
( ( b6 <= b1 implies b5 . b6 = (((Coef b1) . b6) * (b3 #N b6)) * (b4 #N (b1 -' b6)) ) & ( b1 < b6 implies b5 . b6 = 0. b2 ) ) );

definition
let c1 be Nat;
let c2 be Banach_Algebra;
let c3, c4 be Element of c2;
func Expan_e c1,c3,c4 -> sequence of a2 means :Def7: :: LOPBAN_4:def 7
for b1 being Nat holds
( ( b1 <= a1 implies a5 . b1 = (((Coef_e a1) . b1) * (a3 #N b1)) * (a4 #N (a1 -' b1)) ) & ( a1 < b1 implies a5 . b1 = 0. a2 ) );
existence
ex b1 being sequence of c2 st
for b2 being Nat holds
( ( b2 <= c1 implies b1 . b2 = (((Coef_e c1) . b2) * (c3 #N b2)) * (c4 #N (c1 -' b2)) ) & ( c1 < b2 implies b1 . b2 = 0. c2 ) )
proof end;
uniqueness
for b1, b2 being sequence of c2 st ( for b3 being Nat holds
( ( b3 <= c1 implies b1 . b3 = (((Coef_e c1) . b3) * (c3 #N b3)) * (c4 #N (c1 -' b3)) ) & ( c1 < b3 implies b1 . b3 = 0. c2 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c1 implies b2 . b3 = (((Coef_e c1) . b3) * (c3 #N b3)) * (c4 #N (c1 -' b3)) ) & ( c1 < b3 implies b2 . b3 = 0. c2 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def7 defines Expan_e LOPBAN_4:def 7 :
for b1 being Nat
for b2 being Banach_Algebra
for b3, b4 being Element of b2
for b5 being sequence of b2 holds
( b5 = Expan_e b1,b3,b4 iff for b6 being Nat holds
( ( b6 <= b1 implies b5 . b6 = (((Coef_e b1) . b6) * (b3 #N b6)) * (b4 #N (b1 -' b6)) ) & ( b1 < b6 implies b5 . b6 = 0. b2 ) ) );

definition
let c1 be Nat;
let c2 be Banach_Algebra;
let c3, c4 be Element of c2;
func Alfa c1,c3,c4 -> sequence of a2 means :Def8: :: LOPBAN_4:def 8
for b1 being Nat holds
( ( b1 <= a1 implies a5 . b1 = ((a3 ExpSeq ) . b1) * ((Partial_Sums (a4 ExpSeq )) . (a1 -' b1)) ) & ( a1 < b1 implies a5 . b1 = 0. a2 ) );
existence
ex b1 being sequence of c2 st
for b2 being Nat holds
( ( b2 <= c1 implies b1 . b2 = ((c3 ExpSeq ) . b2) * ((Partial_Sums (c4 ExpSeq )) . (c1 -' b2)) ) & ( c1 < b2 implies b1 . b2 = 0. c2 ) )
proof end;
uniqueness
for b1, b2 being sequence of c2 st ( for b3 being Nat holds
( ( b3 <= c1 implies b1 . b3 = ((c3 ExpSeq ) . b3) * ((Partial_Sums (c4 ExpSeq )) . (c1 -' b3)) ) & ( c1 < b3 implies b1 . b3 = 0. c2 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c1 implies b2 . b3 = ((c3 ExpSeq ) . b3) * ((Partial_Sums (c4 ExpSeq )) . (c1 -' b3)) ) & ( c1 < b3 implies b2 . b3 = 0. c2 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def8 defines Alfa LOPBAN_4:def 8 :
for b1 being Nat
for b2 being Banach_Algebra
for b3, b4 being Element of b2
for b5 being sequence of b2 holds
( b5 = Alfa b1,b3,b4 iff for b6 being Nat holds
( ( b6 <= b1 implies b5 . b6 = ((b3 ExpSeq ) . b6) * ((Partial_Sums (b4 ExpSeq )) . (b1 -' b6)) ) & ( b1 < b6 implies b5 . b6 = 0. b2 ) ) );

definition
let c1 be Banach_Algebra;
let c2, c3 be Element of c1;
let c4 be Nat;
func Conj c4,c2,c3 -> sequence of a1 means :Def9: :: LOPBAN_4:def 9
for b1 being Nat holds
( ( b1 <= a4 implies a5 . b1 = ((a2 ExpSeq ) . b1) * (((Partial_Sums (a3 ExpSeq )) . a4) - ((Partial_Sums (a3 ExpSeq )) . (a4 -' b1))) ) & ( a4 < b1 implies a5 . b1 = 0. a1 ) );
existence
ex b1 being sequence of c1 st
for b2 being Nat holds
( ( b2 <= c4 implies b1 . b2 = ((c2 ExpSeq ) . b2) * (((Partial_Sums (c3 ExpSeq )) . c4) - ((Partial_Sums (c3 ExpSeq )) . (c4 -' b2))) ) & ( c4 < b2 implies b1 . b2 = 0. c1 ) )
proof end;
uniqueness
for b1, b2 being sequence of c1 st ( for b3 being Nat holds
( ( b3 <= c4 implies b1 . b3 = ((c2 ExpSeq ) . b3) * (((Partial_Sums (c3 ExpSeq )) . c4) - ((Partial_Sums (c3 ExpSeq )) . (c4 -' b3))) ) & ( c4 < b3 implies b1 . b3 = 0. c1 ) ) ) & ( for b3 being Nat holds
( ( b3 <= c4 implies b2 . b3 = ((c2 ExpSeq ) . b3) * (((Partial_Sums (c3 ExpSeq )) . c4) - ((Partial_Sums (c3 ExpSeq )) . (c4 -' b3))) ) & ( c4 < b3 implies b2 . b3 = 0. c1 ) ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def9 defines Conj LOPBAN_4:def 9 :
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being Nat
for b5 being sequence of b1 holds
( b5 = Conj b4,b2,b3 iff for b6 being Nat holds
( ( b6 <= b4 implies b5 . b6 = ((b2 ExpSeq ) . b6) * (((Partial_Sums (b3 ExpSeq )) . b4) - ((Partial_Sums (b3 ExpSeq )) . (b4 -' b6))) ) & ( b4 < b6 implies b5 . b6 = 0. b1 ) ) );

theorem Th14: :: LOPBAN_4:14
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being Nat holds
( (b2 ExpSeq ) . (b3 + 1) = ((1 / (b3 + 1)) * b2) * ((b2 ExpSeq ) . b3) & (b2 ExpSeq ) . 0 = 1. b1 & ||.((b2 ExpSeq ) . b3).|| <= (||.b2.|| ExpSeq ) . b3 )
proof end;

theorem Th15: :: LOPBAN_4:15
for b1 being Banach_Algebra
for b2 being Nat
for b3 being sequence of b1 st 0 < b2 holds
(Sift b3) . b2 = b3 . (b2 -' 1)
proof end;

theorem Th16: :: LOPBAN_4:16
for b1 being Banach_Algebra
for b2 being Nat
for b3 being sequence of b1 holds (Partial_Sums b3) . b2 = ((Partial_Sums (Sift b3)) . b2) + (b3 . b2)
proof end;

theorem Th17: :: LOPBAN_4:17
for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being Element of b1 st b3,b4 are_commutative holds
(b3 + b4) #N b2 = (Partial_Sums (Expan b2,b3,b4)) . b2
proof end;

theorem Th18: :: LOPBAN_4:18
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being Nat holds Expan_e b4,b2,b3 = (1 / (b4 ! )) * (Expan b4,b2,b3)
proof end;

theorem Th19: :: LOPBAN_4:19
for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being Element of b1 st b3,b4 are_commutative holds
(1 / (b2 ! )) * ((b3 + b4) #N b2) = (Partial_Sums (Expan_e b2,b3,b4)) . b2
proof end;

theorem Th20: :: LOPBAN_4:20
for b1 being Banach_Algebra holds
( (0. b1) ExpSeq is norm_summable & Sum ((0. b1) ExpSeq ) = 1. b1 )
proof end;

registration
let c1 be Banach_Algebra;
let c2 be Element of c1;
cluster a2 ExpSeq -> norm_summable ;
coherence
c2 ExpSeq is norm_summable
proof end;
end;

theorem Th21: :: LOPBAN_4:21
for b1 being Banach_Algebra
for b2, b3 being Element of b1 holds
( (b2 ExpSeq ) . 0 = 1. b1 & (Expan 0,b2,b3) . 0 = 1. b1 )
proof end;

theorem Th22: :: LOPBAN_4:22
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4, b5 being Nat st b4 <= b5 holds
(Alfa (b5 + 1),b2,b3) . b4 = ((Alfa b5,b2,b3) . b4) + ((Expan_e (b5 + 1),b2,b3) . b4)
proof end;

theorem Th23: :: LOPBAN_4:23
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being Nat holds (Partial_Sums (Alfa (b4 + 1),b2,b3)) . b4 = ((Partial_Sums (Alfa b4,b2,b3)) . b4) + ((Partial_Sums (Expan_e (b4 + 1),b2,b3)) . b4)
proof end;

theorem Th24: :: LOPBAN_4:24
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being Nat holds (b2 ExpSeq ) . b4 = (Expan_e b4,b2,b3) . b4
proof end;

theorem Th25: :: LOPBAN_4:25
for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being Element of b1 st b3,b4 are_commutative holds
(Partial_Sums ((b3 + b4) ExpSeq )) . b2 = (Partial_Sums (Alfa b2,b3,b4)) . b2
proof end;

theorem Th26: :: LOPBAN_4:26
for b1 being Banach_Algebra
for b2 being Nat
for b3, b4 being Element of b1 st b3,b4 are_commutative holds
(((Partial_Sums (b3 ExpSeq )) . b2) * ((Partial_Sums (b4 ExpSeq )) . b2)) - ((Partial_Sums ((b3 + b4) ExpSeq )) . b2) = (Partial_Sums (Conj b2,b3,b4)) . b2
proof end;

theorem Th27: :: LOPBAN_4:27
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being Nat holds 0 <= (||.b2.|| ExpSeq ) . b3
proof end;

theorem Th28: :: LOPBAN_4:28
for b1 being Banach_Algebra
for b2 being Element of b1
for b3 being Nat holds
( ||.((Partial_Sums (b2 ExpSeq )) . b3).|| <= (Partial_Sums (||.b2.|| ExpSeq )) . b3 & (Partial_Sums (||.b2.|| ExpSeq )) . b3 <= Sum (||.b2.|| ExpSeq ) & ||.((Partial_Sums (b2 ExpSeq )) . b3).|| <= Sum (||.b2.|| ExpSeq ) )
proof end;

theorem Th29: :: LOPBAN_4:29
for b1 being Banach_Algebra
for b2 being Element of b1 holds 1 <= Sum (||.b2.|| ExpSeq )
proof end;

theorem Th30: :: LOPBAN_4:30
for b1 being Banach_Algebra
for b2 being Element of b1
for b3, b4 being Nat holds
( abs ((Partial_Sums (||.b2.|| ExpSeq )) . b3) = (Partial_Sums (||.b2.|| ExpSeq )) . b3 & ( b3 <= b4 implies abs (((Partial_Sums (||.b2.|| ExpSeq )) . b4) - ((Partial_Sums (||.b2.|| ExpSeq )) . b3)) = ((Partial_Sums (||.b2.|| ExpSeq )) . b4) - ((Partial_Sums (||.b2.|| ExpSeq )) . b3) ) )
proof end;

theorem Th31: :: LOPBAN_4:31
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4, b5 being Nat holds abs ((Partial_Sums ||.(Conj b4,b2,b3).||) . b5) = (Partial_Sums ||.(Conj b4,b2,b3).||) . b5
proof end;

theorem Th32: :: LOPBAN_4:32
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being real number st b4 > 0 holds
ex b5 being Nat st
for b6 being Nat st b5 <= b6 holds
abs ((Partial_Sums ||.(Conj b6,b2,b3).||) . b6) < b4
proof end;

theorem Th33: :: LOPBAN_4:33
for b1 being Banach_Algebra
for b2, b3 being Element of b1
for b4 being sequence of b1 st ( for b5 being Nat holds b4 . b5 = (Partial_Sums (Conj b5,b2,b3)) . b5 ) holds
( b4 is convergent & lim b4 = 0. b1 )
proof end;

Lemma45: for b1 being Banach_Algebra
for b2, b3 being Element of b1 st b2,b3 are_commutative holds
(Sum (b2 ExpSeq )) * (Sum (b3 ExpSeq )) = Sum ((b2 + b3) ExpSeq )
proof end;

definition
let c1 be Banach_Algebra;
func exp_ c1 -> Function of the carrier of a1,the carrier of a1 means :Def10: :: LOPBAN_4:def 10
for b1 being Element of a1 holds a2 . b1 = Sum (b1 ExpSeq );
existence
ex b1 being Function of the carrier of c1,the carrier of c1 st
for b2 being Element of c1 holds b1 . b2 = Sum (b2 ExpSeq )
proof end;
uniqueness
for b1, b2 being Function of the carrier of c1,the carrier of c1 st ( for b3 being Element of c1 holds b1 . b3 = Sum (b3 ExpSeq ) ) & ( for b3 being Element of c1 holds b2 . b3 = Sum (b3 ExpSeq ) ) holds
b1 = b2
proof end;
end;

:: deftheorem Def10 defines exp_ LOPBAN_4:def 10 :
for b1 being Banach_Algebra
for b2 being Function of the carrier of b1,the carrier of b1 holds
( b2 = exp_ b1 iff for b3 being Element of b1 holds b2 . b3 = Sum (b3 ExpSeq ) );

definition
let c1 be Banach_Algebra;
let c2 be Element of c1;
func exp c2 -> Element of a1 equals :: LOPBAN_4:def 11
(exp_ a1) . a2;
correctness
coherence
(exp_ c1) . c2 is Element of c1
;
;
end;

:: deftheorem Def11 defines exp LOPBAN_4:def 11 :
for b1 being Banach_Algebra
for b2 being Element of b1 holds exp b2 = (exp_ b1) . b2;

theorem Th34: :: LOPBAN_4:34
for b1 being Banach_Algebra
for b2 being Element of b1 holds exp b2 = Sum (b2 ExpSeq ) by Def10;

theorem Th35: :: LOPBAN_4:35
for b1 being Banach_Algebra
for b2, b3 being Element of b1 st b2,b3 are_commutative holds
( exp (b2 + b3) = (exp b2) * (exp b3) & exp (b3 + b2) = (exp b3) * (exp b2) & exp (b2 + b3) = exp (b3 + b2) & exp b2, exp b3 are_commutative )
proof end;

theorem Th36: :: LOPBAN_4:36
for b1 being Banach_Algebra
for b2, b3 being Element of b1 st b2,b3 are_commutative holds
b2 * (exp b3) = (exp b3) * b2
proof end;

theorem Th37: :: LOPBAN_4:37
for b1 being Banach_Algebra holds exp (0. b1) = 1. b1
proof end;

theorem Th38: :: LOPBAN_4:38
for b1 being Banach_Algebra
for b2 being Element of b1 holds
( (exp b2) * (exp (- b2)) = 1. b1 & (exp (- b2)) * (exp b2) = 1. b1 )
proof end;

theorem Th39: :: LOPBAN_4:39
for b1 being Banach_Algebra
for b2 being Element of b1 holds
( exp b2 is invertible & (exp b2) " = exp (- b2) & exp (- b2) is invertible & (exp (- b2)) " = exp b2 )
proof end;

theorem Th40: :: LOPBAN_4:40
for b1 being Banach_Algebra
for b2 being Element of b1
for b3, b4 being Real holds b3 * b2,b4 * b2 are_commutative
proof end;

theorem Th41: :: LOPBAN_4:41
for b1 being Banach_Algebra
for b2 being Element of b1
for b3, b4 being Real holds
( (exp (b3 * b2)) * (exp (b4 * b2)) = exp ((b3 + b4) * b2) & (exp (b4 * b2)) * (exp (b3 * b2)) = exp ((b4 + b3) * b2) & exp ((b3 + b4) * b2) = exp ((b4 + b3) * b2) & exp (b3 * b2), exp (b4 * b2) are_commutative )
proof end;