theorem
  vector(LC_CLSpace V,L1) - vector(LC_CLSpace V,L2) = L1 - L2
proof
  - L2 in C_LinComb V by Def12;
  then
A1: - L2 in LC_CLSpace V;
  - vector(LC_CLSpace V,L2) = - L2 by Th40
    .= vector(LC_CLSpace V,- L2) by A1,RLVECT_2:def 1;
  hence thesis by Th38;
end;
