theorem
  for n, m be Nat
  for M be Matrix of n,m,F_Real
  for A be linearly-independent Subset of REAL-NS n
    st the_rank_of M = n
  holds
    (Mx2Tran M) .: A is linearly-independent
  proof
    let n, m be Nat;
    let M be Matrix of n,m,F_Real;
    let A be linearly-independent Subset of REAL-NS n;
    assume
    A1: the_rank_of M = n;

    reconsider A0 = A as linearly-independent Subset of TOP-REAL n
      by Th4,Th28;
    (Mx2Tran M) .: A0 is linearly-independent by A1,MATRTOP2:23;
    hence thesis;
  end;
