
theorem Th17:
  for S be non empty finite set, s be non empty FinSequence of S
  holds Sum FDprobSEQ (s) = 1
proof
  let S be non empty finite set, s be non empty FinSequence of S;
  Sum freqSEQ(s) = len s by Th16;
  then (len s)* Sum(FDprobSEQ s) = (len s)*1 by Th13;
  hence thesis by XCMPLX_1:5;
end;
