reserve p,q,r for FinSequence,
  x,y for object;

theorem Th12:
  for R being Relation, a being object holds R reduces a,a
proof
  let R be Relation;
  let a be object;
  reconsider p = <*a*> as RedSequence of R by Th6;
  take p;
  len p = 1 by FINSEQ_1:40;
  hence thesis;
end;
