
theorem Th4:
  for S be finite set, s,t,u be FinSequence of S st
  s,t -are_prob_equivalent & t,u -are_prob_equivalent holds
  s,u -are_prob_equivalent
proof
  let S be finite set;
  let s,t,u be FinSequence of S;
  assume that
A1: s,t -are_prob_equivalent and
A2: t,u -are_prob_equivalent;
  let x be set;
  thus FDprobability (x,s)=FDprobability (x,t) by A1
    .=FDprobability (x,u) by A2;
end;
