mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced separators="|"><mrow><mi mathvariant="normal">a</mi><mo>+</mo><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></mfenced><mfenced separators="|"><mrow><mi mathvariant="normal">a</mi><mo>-</mo><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></mfenced></math>