reserve f,g,h for Function,
  A for set;
reserve F for Function,
  B,x,y,y1,y2,z for set;
reserve x,z for object;
reserve X for non empty set,
  Y for set,
  F for BinOp of X,
  f,g,h for Function of Y,X,
  x,x1,x2 for Element of X;

theorem Th36:
  F.:(f,g) is Function of Y,X
proof
  F*<:f,g:> is Function of Y,X;
  hence thesis;
end;
