theorem Th39:
  for vt being finite DecoratedTree st vt is_an_evaluation_of t,f
  holds t@f = vt.{}
proof
A1: ex e being finite DecoratedTree st e is_an_evaluation_of t,f & t@f = e
  .{} by Def10;
  let vt be finite DecoratedTree;
  assume vt is_an_evaluation_of t,f;
  hence thesis by A1,Th37;
end;
