let n, m be Nat; for M being Matrix of n,m,F_Real st the_rank_of M = n holds
M is OrdBasis of Lin (lines M)
let M be Matrix of n,m,F_Real; ( the_rank_of M = n implies M is OrdBasis of Lin (lines M) )
A1:
lines M c= [#] (Lin (lines M))
by Lm4;
then reconsider L = lines M as Subset of (Lin (lines M)) ;
reconsider B = M as FinSequence of (Lin (lines M)) by A1, FINSEQ_1:def 4;
assume A2:
the_rank_of M = n
; M is OrdBasis of Lin (lines M)
A3:
M is one-to-one
by A2, MATRIX13:121;
lines M is linearly-independent
by A2, MATRIX13:121;
then A4:
L is linearly-independent
by VECTSP_9:12;
Lin L = Lin (lines M)
by VECTSP_9:17;
then
L is Basis of (Lin (lines M))
by A4, VECTSP_7:def 3;
then
B is OrdBasis of Lin (lines M)
by A3, MATRLIN:def 2;
hence
M is OrdBasis of Lin (lines M)
; verum