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

theorem
  for R being Relation, C being Completion of R holds R,C are_equivalent
proof
  let R be Relation, C be Completion of R, a,b be object;
  a,b are_convertible_wrt R iff a,b are_convergent_wrt C by Def28;
  hence thesis by Def23,Th37;
end;
