mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mtable><mtr><mtd><mi mathvariant="normal">f</mi></mtd><mtd><mi mathvariant="normal">d</mi></mtd><mtd><mtable><mtr><mtd><mi mathvariant="normal">v</mi></mtd><mtd/></mtr></mtable></mtd></mtr><mtr><mtd><mi>zf</mi></mtd><mtd><mi>zz</mi></mtd><mtd><mtable><mtr><mtd><mi mathvariant="normal">g</mi></mtd><mtd><mi>gf</mi></mtd></mtr></mtable></mtd></mtr><mtr><mtd><mi mathvariant="normal">f</mi></mtd><mtd><mi mathvariant="normal">f</mi></mtd><mtd><mtable><mtr><mtd><mi mathvariant="normal">f</mi></mtd><mtd><mi mathvariant="normal">f</mi></mtd></mtr></mtable></mtd></mtr></mtable></math>