theorem Th32:
  <*x,y*> is FinTree-yielding iff x is finite Tree & y is finite Tree
proof
A1: x is finite Tree & y is finite Tree iff {x,y} is constituted-FinTrees
  by Th16;
  rng <*x,y*> = {x,y} by FINSEQ_2:127;
  hence thesis by A1;
end;
