theorem Th29:
 for x being object holds
  <*x*> is FinTree-yielding iff x is finite Tree
proof let x be object;
A1: x is finite Tree iff {x} is constituted-FinTrees by Th13;
  rng <*x*> = {x} by FINSEQ_1:39;
  hence thesis by A1;
end;
