theorem Th6:
  for p, q being XFinSequence st <%x%>^p = <%y%>^q holds x = y & p = q
proof
  let p, q be XFinSequence such that
A1: <%x%>^p = <%y%>^q;
  (<%x%>^p).0 = x by AFINSQ_1:35;
  then x = y by A1,AFINSQ_1:35;
  hence thesis by A1,AFINSQ_1:28;
end;
