
theorem Th13:
  for S be finite set, s be FinSequence of S holds
  Sum (freqSEQ (s))=(len s)* Sum(FDprobSEQ(s))
proof
  let S be finite set, s be FinSequence of S;
  freqSEQ (s) =(len s)*FDprobSEQ(s) by Th12;
  hence thesis by RVSUM_1:87;
end;
