mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">A</mi><mo>=</mo><mfenced open="[" close="]" separators="|"><mtable><mtr><mtd><mn>2</mn></mtd><mtd><mn>7</mn></mtd></mtr><mtr><mtd><mn>1</mn></mtd><mtd><mn>5</mn></mtd></mtr></mtable></mfenced></math>