theorem Th68:
  for a being Element of COMPLEX, x,y being FinSequence of COMPLEX
  st len x=len y holds |(x,a*y)| = (a*')*(|(x,y)|)
proof
  let a be Element of COMPLEX, x,y be FinSequence of COMPLEX;
  assume
A1: len x=len y;
  |(x,a*y)|=(|(a*y,x)|)*' by Th64
    .=(a*|(y,x)|)*' by A1,Th67
    .=(a*')*(|(y,x)|)*' by COMPLEX1:35
    .=(a*')*(|(x,y)|) by Th64;
  hence thesis;
end;
