reserve i,j,x,y for object,
  f,g for Function;

theorem Th3:
  for I being set holds uncurry (I --> {}) = {}
proof
  let I be set;
  per cases;
  suppose
    I = {};
    hence thesis by FUNCT_5:43;
  end;
  suppose
    I <> {};
    then rng (I --> {}) = {{}} by FUNCOP_1:8
      .= Funcs({} qua set, {} qua set) by FUNCT_5:57;
    then dom uncurry (I --> {}) = [:dom (I --> {}), {}:] by FUNCT_5:26
      .= {} by ZFMISC_1:90;
    hence thesis;
  end;
end;
