let V be RealLinearSpace; :: thesis: for M being convex Subset of V
for N being Subset of V
for L being Linear_Combination of N st L is convex & N c= M holds
Sum L in M
let M be convex Subset of V; :: thesis: for N being Subset of V
for L being Linear_Combination of N st L is convex & N c= M holds
Sum L in M
let N be Subset of V; :: thesis: for L being Linear_Combination of N st L is convex & N c= M holds
Sum L in M
let L be Linear_Combination of N; :: thesis: ( L is convex & N c= M implies Sum L in M )
assume that
A1:
L is convex
and
A2:
N c= M
; :: thesis: Sum L in M
consider F being FinSequence of the carrier of V such that
A3:
F is one-to-one
and
A4:
rng F = Carrier L
and
A5:
ex f being FinSequence of REAL st
( len f = len F & Sum f = 1 & ( for n being Nat st n in dom f holds
( f . n = L . (F . n) & f . n >= 0 ) ) )
by A1, CONVEX1:def 3;
consider f being FinSequence of REAL such that
A6:
len f = len F
and
A7:
Sum f = 1
and
A8:
for n being Nat st n in dom f holds
( f . n = L . (F . n) & f . n >= 0 )
by A5;
A9:
len F >= 1
then reconsider i = len F as non empty Element of NAT ;
defpred S1[ Nat] means (1 / (Sum (mid f,1,$1))) * (Sum (mid (L (#) F),1,$1)) in M;
A10:
len (L (#) F) = len F
by RLVECT_2:def 9;
A11:
S1[1]
proof
mid f,1,1
= f | 1
by JORDAN3:25;
then A12:
len (mid f,1,1) = 1
by A6, A9, FINSEQ_1:80;
then
1
in dom (mid f,1,1)
by FINSEQ_3:27;
then reconsider m =
(mid f,1,1) . 1 as
Element of
REAL by PARTFUN1:27;
mid f,1,1
= <*((mid f,1,1) . 1)*>
by A12, FINSEQ_1:57;
then A13:
Sum (mid f,1,1) = m
by FINSOP_1:12;
mid (L (#) F),1,1
= (L (#) F) | 1
by JORDAN3:25;
then A14:
len (mid (L (#) F),1,1) = 1
by A9, A10, FINSEQ_1:80;
1
in Seg (len (L (#) F))
by A9, A10;
then A15:
( 1
in dom (L (#) F) & 1
in dom F & 1
in dom f )
by A6, A10, FINSEQ_1:def 3;
then A16:
F /. 1
= F . 1
by PARTFUN1:def 8;
A17:
(mid (L (#) F),1,1) . 1 =
(L (#) F) . 1
by A9, A10, JORDAN3:32
.=
(L . (F /. 1)) * (F /. 1)
by A15, RLVECT_2:def 9
;
f . 1 =
L . (F . 1)
by A8, A15
.=
L . (F /. 1)
by A15, PARTFUN1:def 8
;
then A18:
Sum (mid f,1,1) = L . (F /. 1)
by A6, A9, A13, JORDAN3:32;
A19:
F . 1
in rng F
by A15, FUNCT_1:def 5;
then
F . 1
in { v where v is Element of V : L . v <> 0 }
by A4, RLVECT_2:def 6;
then consider v2 being
Element of
V such that A20:
(
F . 1
= v2 &
L . v2 <> 0 )
;
mid (L (#) F),1,1
= <*((mid (L (#) F),1,1) . 1)*>
by A14, FINSEQ_1:57;
then A21:
(1 / (Sum (mid f,1,1))) * (Sum (mid (L (#) F),1,1)) =
(1 / (Sum (mid f,1,1))) * ((L . (F /. 1)) * (F /. 1))
by A17, RLVECT_1:61
.=
((1 / (Sum (mid f,1,1))) * (L . (F /. 1))) * (F /. 1)
by RLVECT_1:def 9
.=
1
* (F /. 1)
by A16, A18, A20, XCMPLX_1:107
.=
F /. 1
by RLVECT_1:def 9
;
Carrier L c= N
by RLVECT_2:def 8;
then
Carrier L c= M
by A2, XBOOLE_1:1;
hence
S1[1]
by A4, A16, A19, A21;
:: thesis: verum
end;
A22:
for k being non empty Nat st S1[k] holds
S1[k + 1]
proof
let k be non
empty Nat;
:: thesis: ( S1[k] implies S1[k + 1] )
assume A23:
(1 / (Sum (mid f,1,k))) * (Sum (mid (L (#) F),1,k)) in M
;
:: thesis: S1[k + 1]
A24:
k >= 1
by NAT_1:14;
now per cases
( k >= len f or k < len f )
;
suppose A25:
k >= len f
;
:: thesis: S1[k + 1]A26:
mid f,1,
k =
f | k
by JORDAN3:25, NAT_1:14
.=
f
by A25, FINSEQ_1:79
;
A27:
mid (L (#) F),1,
k =
(L (#) F) | k
by JORDAN3:25, NAT_1:14
.=
L (#) F
by A6, A10, A25, FINSEQ_1:79
;
A28:
mid f,1,
(k + 1) =
f | (k + 1)
by JORDAN3:25, NAT_1:12
.=
f
by A25, FINSEQ_1:79, NAT_1:12
;
mid (L (#) F),1,
(k + 1) =
(L (#) F) | (k + 1)
by JORDAN3:25, NAT_1:12
.=
L (#) F
by A6, A10, A25, FINSEQ_1:79, NAT_1:12
;
hence
S1[
k + 1]
by A23, A26, A27, A28;
:: thesis: verum end; suppose A29:
k < len f
;
:: thesis: S1[k + 1]then A30:
(
k + 1
>= 1 &
k + 1
<= len f )
by NAT_1:13, NAT_1:14;
mid f,1,
k = f | k
by JORDAN3:25, NAT_1:14;
then A31:
len (mid f,1,k) = k
by A29, FINSEQ_1:80;
A32:
len <*((mid f,1,(k + 1)) . (k + 1))*> = 1
by FINSEQ_1:57;
mid f,1,
(k + 1) = f | (k + 1)
by A30, JORDAN3:25;
then
len (mid f,1,(k + 1)) = k + 1
by A30, FINSEQ_1:80;
then A33:
dom (mid f,1,(k + 1)) = Seg ((len (mid f,1,k)) + (len <*((mid f,1,(k + 1)) . (k + 1))*>))
by A31, A32, FINSEQ_1:def 3;
A34:
mid f,1,
(k + 1) = f | (k + 1)
by A30, JORDAN3:25;
A35:
len (f | (k + 1)) = k + 1
by A30, FINSEQ_1:80;
A36:
for
i being
Nat st
i in dom (mid f,1,k) holds
(mid f,1,(k + 1)) . i = (mid f,1,k) . i
proof
let i be
Nat;
:: thesis: ( i in dom (mid f,1,k) implies (mid f,1,(k + 1)) . i = (mid f,1,k) . i )
A37:
i in NAT
by ORDINAL1:def 13;
assume A38:
i in dom (mid f,1,k)
;
:: thesis: (mid f,1,(k + 1)) . i = (mid f,1,k) . i
A39:
mid f,1,
k = f | k
by JORDAN3:25, NAT_1:14;
then
(f | k) . i = (f | k) /. i
by A38, PARTFUN1:def 8;
then A40:
(mid f,1,k) . i = f /. i
by A38, A39, FINSEQ_4:85;
A41:
i in Seg (len (f | k))
by A38, A39, FINSEQ_1:def 3;
len (f | k) = k
by A29, FINSEQ_1:80;
then
( 1
<= i &
i <= k )
by A41, FINSEQ_1:3;
then
( 1
<= i &
i <= k + 1 )
by NAT_1:12;
then
i in Seg (k + 1)
by A37;
then A42:
i in dom (f | (k + 1))
by A35, FINSEQ_1:def 3;
then
(f | (k + 1)) . i = (f | (k + 1)) /. i
by PARTFUN1:def 8;
hence
(mid f,1,(k + 1)) . i = (mid f,1,k) . i
by A34, A40, A42, FINSEQ_4:85;
:: thesis: verum
end;
for
i being
Nat st
i in dom <*((mid f,1,(k + 1)) . (k + 1))*> holds
(mid f,1,(k + 1)) . ((len (mid f,1,k)) + i) = <*((mid f,1,(k + 1)) . (k + 1))*> . i
proof
let i be
Nat;
:: thesis: ( i in dom <*((mid f,1,(k + 1)) . (k + 1))*> implies (mid f,1,(k + 1)) . ((len (mid f,1,k)) + i) = <*((mid f,1,(k + 1)) . (k + 1))*> . i )
assume
i in dom <*((mid f,1,(k + 1)) . (k + 1))*>
;
:: thesis: (mid f,1,(k + 1)) . ((len (mid f,1,k)) + i) = <*((mid f,1,(k + 1)) . (k + 1))*> . i
then
i in Seg 1
by FINSEQ_1:55;
then
i = 1
by FINSEQ_1:4, TARSKI:def 1;
hence
(mid f,1,(k + 1)) . ((len (mid f,1,k)) + i) = <*((mid f,1,(k + 1)) . (k + 1))*> . i
by A31, FINSEQ_1:57;
:: thesis: verum
end; then A43:
mid f,1,
(k + 1) = (mid f,1,k) ^ <*((mid f,1,(k + 1)) . (k + 1))*>
by A33, A36, FINSEQ_1:def 7;
k + 1
in Seg (k + 1)
by A30;
then A44:
k + 1
in dom (f | (k + 1))
by A35, FINSEQ_1:def 3;
then
(f | (k + 1)) /. (k + 1) = f /. (k + 1)
by FINSEQ_4:85;
then A45:
(mid f,1,(k + 1)) . (k + 1) = f /. (k + 1)
by A34, A44, PARTFUN1:def 8;
A46:
k + 1
in Seg (len f)
by A30;
then A47:
k + 1
in dom f
by FINSEQ_1:def 3;
then A48:
(mid f,1,(k + 1)) . (k + 1) =
f . (k + 1)
by A45, PARTFUN1:def 8
.=
L . (F . (k + 1))
by A8, A47
;
k + 1
in dom F
by A6, A46, FINSEQ_1:def 3;
then
(mid f,1,(k + 1)) . (k + 1) = L . (F /. (k + 1))
by A48, PARTFUN1:def 8;
then A49:
Sum (mid f,1,(k + 1)) = (Sum (mid f,1,k)) + (L . (F /. (k + 1)))
by A43, RVSUM_1:104;
A50:
k < len (L (#) F)
by A6, A29, RLVECT_2:def 9;
then A51:
(
k + 1
>= 1 &
k + 1
<= len (L (#) F) )
by NAT_1:13, NAT_1:14;
mid (L (#) F),1,
k = (L (#) F) | k
by JORDAN3:25, NAT_1:14;
then A52:
len (mid (L (#) F),1,k) = k
by A50, FINSEQ_1:80;
A53:
len <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> = 1
by FINSEQ_1:57;
A54:
mid (L (#) F),1,
(k + 1) = (L (#) F) | (k + 1)
by A51, JORDAN3:25;
then
len (mid (L (#) F),1,(k + 1)) = k + 1
by A51, FINSEQ_1:80;
then A55:
dom (mid (L (#) F),1,(k + 1)) = Seg ((len (mid (L (#) F),1,k)) + (len <*((mid (L (#) F),1,(k + 1)) . (k + 1))*>))
by A52, A53, FINSEQ_1:def 3;
A56:
len ((L (#) F) | (k + 1)) = k + 1
by A51, FINSEQ_1:80;
A57:
for
i being
Nat st
i in dom (mid (L (#) F),1,k) holds
(mid (L (#) F),1,(k + 1)) . i = (mid (L (#) F),1,k) . i
proof
let i be
Nat;
:: thesis: ( i in dom (mid (L (#) F),1,k) implies (mid (L (#) F),1,(k + 1)) . i = (mid (L (#) F),1,k) . i )
A58:
i in NAT
by ORDINAL1:def 13;
assume A59:
i in dom (mid (L (#) F),1,k)
;
:: thesis: (mid (L (#) F),1,(k + 1)) . i = (mid (L (#) F),1,k) . i
A60:
mid (L (#) F),1,
k = (L (#) F) | k
by JORDAN3:25, NAT_1:14;
then
((L (#) F) | k) . i = ((L (#) F) | k) /. i
by A59, PARTFUN1:def 8;
then A61:
(mid (L (#) F),1,k) . i = (L (#) F) /. i
by A59, A60, FINSEQ_4:85;
A62:
i in Seg (len ((L (#) F) | k))
by A59, A60, FINSEQ_1:def 3;
len ((L (#) F) | k) = k
by A50, FINSEQ_1:80;
then
( 1
<= i &
i <= k )
by A62, FINSEQ_1:3;
then
( 1
<= i &
i <= k + 1 )
by NAT_1:12;
then
i in Seg (k + 1)
by A58;
then A63:
i in dom ((L (#) F) | (k + 1))
by A56, FINSEQ_1:def 3;
then
((L (#) F) | (k + 1)) . i = ((L (#) F) | (k + 1)) /. i
by PARTFUN1:def 8;
hence
(mid (L (#) F),1,(k + 1)) . i = (mid (L (#) F),1,k) . i
by A54, A61, A63, FINSEQ_4:85;
:: thesis: verum
end;
for
i being
Nat st
i in dom <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> holds
(mid (L (#) F),1,(k + 1)) . ((len (mid (L (#) F),1,k)) + i) = <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> . i
proof
let i be
Nat;
:: thesis: ( i in dom <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> implies (mid (L (#) F),1,(k + 1)) . ((len (mid (L (#) F),1,k)) + i) = <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> . i )
assume
i in dom <*((mid (L (#) F),1,(k + 1)) . (k + 1))*>
;
:: thesis: (mid (L (#) F),1,(k + 1)) . ((len (mid (L (#) F),1,k)) + i) = <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> . i
then
i in Seg 1
by FINSEQ_1:55;
then
i = 1
by FINSEQ_1:4, TARSKI:def 1;
hence
(mid (L (#) F),1,(k + 1)) . ((len (mid (L (#) F),1,k)) + i) = <*((mid (L (#) F),1,(k + 1)) . (k + 1))*> . i
by A52, FINSEQ_1:57;
:: thesis: verum
end; then A64:
mid (L (#) F),1,
(k + 1) = (mid (L (#) F),1,k) ^ <*((mid (L (#) F),1,(k + 1)) . (k + 1))*>
by A55, A57, FINSEQ_1:def 7;
k + 1
in Seg (k + 1)
by A30;
then A65:
k + 1
in dom ((L (#) F) | (k + 1))
by A56, FINSEQ_1:def 3;
then
((L (#) F) | (k + 1)) /. (k + 1) = (L (#) F) /. (k + 1)
by FINSEQ_4:85;
then A66:
(mid (L (#) F),1,(k + 1)) . (k + 1) = (L (#) F) /. (k + 1)
by A54, A65, PARTFUN1:def 8;
k + 1
<= len (L (#) F)
by A6, A30, RLVECT_2:def 9;
then A67:
k + 1
in dom (L (#) F)
by A30, FINSEQ_3:27;
then A68:
(mid (L (#) F),1,(k + 1)) . (k + 1) =
(L (#) F) . (k + 1)
by A66, PARTFUN1:def 8
.=
(L . (F /. (k + 1))) * (F /. (k + 1))
by A67, RLVECT_2:def 9
;
set r1 =
Sum (mid f,1,k);
set r2 =
L . (F /. (k + 1));
set w1 =
Sum (mid (L (#) F),1,k);
set w2 =
F /. (k + 1);
A69:
for
i being
Nat st
i in dom (mid f,1,k) holds
0 <= (mid f,1,k) . i
proof
let i be
Nat;
:: thesis: ( i in dom (mid f,1,k) implies 0 <= (mid f,1,k) . i )
assume
i in dom (mid f,1,k)
;
:: thesis: 0 <= (mid f,1,k) . i
then
i in Seg k
by A31, FINSEQ_1:def 3;
then A71:
( 1
<= i &
i <= k )
by FINSEQ_1:3;
then A72:
(mid f,1,k) . i = f . i
by A29, JORDAN3:32;
( 1
<= i &
i <= len f )
by A29, A71, XXREAL_0:2;
then
i in dom f
by FINSEQ_3:27;
hence
0 <= (mid f,1,k) . i
by A8, A72;
:: thesis: verum
end;
ex
i being
Element of
NAT st
(
i in dom (mid f,1,k) &
0 < (mid f,1,k) . i )
proof
A73:
1
in Seg (len (mid f,1,k))
by A24, A31;
1
<= len f
by A29, NAT_1:14;
then A74:
1
in Seg (len f)
;
then
1
in dom f
by FINSEQ_1:def 3;
then A75:
(
f . 1
= L . (F . 1) &
f . 1
>= 0 )
by A8;
1
in dom F
by A6, A74, FINSEQ_1:def 3;
then
F . 1
in Carrier L
by A4, FUNCT_1:def 5;
then
F . 1
in { v where v is Element of V : L . v <> 0 }
by RLVECT_2:def 6;
then consider v being
Element of
V such that A76:
(
v = F . 1 &
L . v <> 0 )
;
take
1
;
:: thesis: ( 1 in dom (mid f,1,k) & 0 < (mid f,1,k) . 1 )
thus
( 1
in dom (mid f,1,k) &
0 < (mid f,1,k) . 1 )
by A24, A29, A73, A75, A76, FINSEQ_1:def 3, JORDAN3:32;
:: thesis: verum
end; then A77:
Sum (mid f,1,k) > 0
by A69, RVSUM_1:115;
A78:
(
F /. (k + 1) in M &
L . (F /. (k + 1)) > 0 )
then A82:
(Sum (mid f,1,k)) + (L . (F /. (k + 1))) > 0 + 0
by A77, XREAL_1:10;
A83:
(
0 < (1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) &
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) < 1 )
proof
1
/ ((Sum (mid f,1,k)) + (L . (F /. (k + 1)))) > 0
by A82, XREAL_1:141;
hence
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) > 0
by A77, XREAL_1:131;
:: thesis: (1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) < 1
A84:
(Sum (mid f,1,k)) + (L . (F /. (k + 1))) > Sum (mid f,1,k)
by A78, XREAL_1:31;
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) = (Sum (mid f,1,k)) / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))
by XCMPLX_1:100;
hence
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)) < 1
by A77, A84, XREAL_1:191;
:: thesis: verum
end; A85:
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (L . (F /. (k + 1))) = 1
- ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)))
proof
1
- ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k))) =
(((Sum (mid f,1,k)) + (L . (F /. (k + 1)))) * (1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1)))))) - ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)))
by A82, XCMPLX_1:107
.=
(((Sum (mid f,1,k)) + (L . (F /. (k + 1)))) - (Sum (mid f,1,k))) * (1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1)))))
;
hence
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (L . (F /. (k + 1))) = 1
- ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k)))
;
:: thesis: verum
end; (1 / (Sum (mid f,1,(k + 1)))) * (Sum (mid (L (#) F),1,(k + 1))) =
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((Sum (mid (L (#) F),1,k)) + ((L . (F /. (k + 1))) * (F /. (k + 1))))
by A49, A64, A68, FVSUM_1:87
.=
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((1 * (Sum (mid (L (#) F),1,k))) + ((L . (F /. (k + 1))) * (F /. (k + 1))))
by RLVECT_1:def 9
.=
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((((Sum (mid f,1,k)) * (1 / (Sum (mid f,1,k)))) * (Sum (mid (L (#) F),1,k))) + ((L . (F /. (k + 1))) * (F /. (k + 1))))
by A77, XCMPLX_1:107
.=
(1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (((Sum (mid f,1,k)) * ((1 / (Sum (mid f,1,k))) * (Sum (mid (L (#) F),1,k)))) + ((L . (F /. (k + 1))) * (F /. (k + 1))))
by RLVECT_1:def 9
.=
((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((Sum (mid f,1,k)) * ((1 / (Sum (mid f,1,k))) * (Sum (mid (L (#) F),1,k))))) + ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((L . (F /. (k + 1))) * (F /. (k + 1))))
by RLVECT_1:def 9
.=
(((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k))) * ((1 / (Sum (mid f,1,k))) * (Sum (mid (L (#) F),1,k)))) + ((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * ((L . (F /. (k + 1))) * (F /. (k + 1))))
by RLVECT_1:def 9
.=
(((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (Sum (mid f,1,k))) * ((1 / (Sum (mid f,1,k))) * (Sum (mid (L (#) F),1,k)))) + (((1 / ((Sum (mid f,1,k)) + (L . (F /. (k + 1))))) * (L . (F /. (k + 1)))) * (F /. (k + 1)))
by RLVECT_1:def 9
;
hence
S1[
k + 1]
by A23, A78, A83, A85, CONVEX1:def 2;
:: thesis: verum end; end; end;
hence
S1[
k + 1]
;
:: thesis: verum
end;
for k being non empty Nat holds S1[k]
from NAT_1:sch 10(A11, A22);
then A86:
(1 / (Sum (mid f,1,i))) * (Sum (mid (L (#) F),1,i)) in M
;
A87:
len (L (#) F) = len F
by RLVECT_2:def 9;
Sum (mid f,1,(len f)) = 1
by A6, A7, A9, JORDAN3:29;
then (1 / (Sum (mid f,1,(len f)))) * (Sum (mid (L (#) F),1,(len (L (#) F)))) =
Sum (mid (L (#) F),1,(len (L (#) F)))
by RLVECT_1:def 9
.=
Sum (L (#) F)
by A9, A87, JORDAN3:29
;
hence
Sum L in M
by A3, A4, A6, A86, A87, RLVECT_2:def 10; :: thesis: verum