let n be Nat; for Affn being affinely-independent Subset of (TOP-REAL n)
for EN being Enumeration of Affn st 0* n in Affn & EN . (len EN) = 0* n holds
( rng (EN | ((card Affn) -' 1)) = Affn \ {(0* n)} & ( for A being Subset of (n -VectSp_over F_Real) st Affn = A holds
EN | ((card Affn) -' 1) is OrdBasis of Lin A ) )
let Affn be affinely-independent Subset of (TOP-REAL n); for EN being Enumeration of Affn st 0* n in Affn & EN . (len EN) = 0* n holds
( rng (EN | ((card Affn) -' 1)) = Affn \ {(0* n)} & ( for A being Subset of (n -VectSp_over F_Real) st Affn = A holds
EN | ((card Affn) -' 1) is OrdBasis of Lin A ) )
let EN be Enumeration of Affn; ( 0* n in Affn & EN . (len EN) = 0* n implies ( rng (EN | ((card Affn) -' 1)) = Affn \ {(0* n)} & ( for A being Subset of (n -VectSp_over F_Real) st Affn = A holds
EN | ((card Affn) -' 1) is OrdBasis of Lin A ) ) )
set A = Affn;
set E = EN;
assume that
A1:
0* n in Affn
and
A2:
EN . (len EN) = 0* n
; ( rng (EN | ((card Affn) -' 1)) = Affn \ {(0* n)} & ( for A being Subset of (n -VectSp_over F_Real) st Affn = A holds
EN | ((card Affn) -' 1) is OrdBasis of Lin A ) )
A3:
card Affn >= 1
by A1, NAT_1:14;
set cA = (card Affn) -' 1;
A4:
rng EN = Affn
by Def1;
(card Affn) -' 1 = (card Affn) - 1
by A1, NAT_1:14, XREAL_1:233;
then A5:
len EN = ((card Affn) -' 1) + 1
by A4, FINSEQ_4:62;
A6:
len EN = card Affn
by A4, FINSEQ_4:62;
A7:
not 0* n in rng (EN | ((card Affn) -' 1))
proof
A8:
len EN in dom EN
by A6, A3, FINSEQ_3:25;
assume
0* n in rng (EN | ((card Affn) -' 1))
;
contradiction
then consider x being
object such that A9:
x in dom (EN | ((card Affn) -' 1))
and A10:
(EN | ((card Affn) -' 1)) . x = 0* n
by FUNCT_1:def 3;
A11:
x in Seg ((card Affn) -' 1)
by A9, RELAT_1:57;
(
x in dom EN &
(EN | ((card Affn) -' 1)) . x = EN . x )
by A9, FUNCT_1:47, RELAT_1:57;
then
x = ((card Affn) -' 1) + 1
by A2, A5, A10, A8, FUNCT_1:def 4;
then
((card Affn) -' 1) + 1
<= (card Affn) -' 1
by A11, FINSEQ_1:1;
hence
contradiction
by NAT_1:13;
verum
end;
EN = (EN | ((card Affn) -' 1)) ^ <*(EN . (len EN))*>
by A5, FINSEQ_3:55;
then A12: Affn =
(rng (EN | ((card Affn) -' 1))) \/ (rng <*(EN . (len EN))*>)
by A4, FINSEQ_1:31
.=
(rng (EN | ((card Affn) -' 1))) \/ {(0* n)}
by A2, FINSEQ_1:38
;
hence A13:
Affn \ {(0* n)} = rng (EN | ((card Affn) -' 1))
by A7, ZFMISC_1:117; for A being Subset of (n -VectSp_over F_Real) st Affn = A holds
EN | ((card Affn) -' 1) is OrdBasis of Lin A
let A1 be Subset of (n -VectSp_over F_Real); ( Affn = A1 implies EN | ((card Affn) -' 1) is OrdBasis of Lin A1 )
assume A14:
Affn = A1
; EN | ((card Affn) -' 1) is OrdBasis of Lin A1
A1 c= [#] (Lin A1)
then reconsider e = EN as FinSequence of (Lin A1) by A4, A14, FINSEQ_1:def 4;
0* n = 0. (TOP-REAL n)
by EUCLID:66;
then
Affn \ {(0* n)} is linearly-independent
by A1, RLAFFIN1:46;
then
A1 \ {(0* n)} is linearly-independent
by A14, MATRTOP2:7;
then A15:
rng (e | ((card Affn) -' 1)) is linearly-independent
by A14, A13, VECTSP_9:12;
[#] (Lin A1) =
[#] (Lin Affn)
by A14, MATRTOP2:6
.=
[#] (Lin (Affn \ {(0. (TOP-REAL n))}))
by Lm2
.=
[#] (Lin (Affn \ {(0* n)}))
by EUCLID:66
.=
[#] (Lin (A1 \ {(0* n)}))
by A14, MATRTOP2:6
;
then Lin A1 =
Lin (A1 \ {(0* n)})
by VECTSP_4:29
.=
Lin (rng (e | ((card Affn) -' 1)))
by A12, A7, A14, VECTSP_9:17, ZFMISC_1:117
;
then
( e | ((card Affn) -' 1) is one-to-one & rng (e | ((card Affn) -' 1)) is Basis of (Lin A1) )
by A15, FUNCT_1:52, VECTSP_7:def 3;
hence
EN | ((card Affn) -' 1) is OrdBasis of Lin A1
by MATRLIN:def 2; verum