mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi mathvariant="normal">v</mi><mn>1</mn></msub><mo>-</mo><msub><mi mathvariant="normal">v</mi><mn>2</mn></msub><mo>=</mo><msup><mfenced open="[" close="]" separators="|"><mrow><mfrac><mrow><mn>2</mn><mi mathvariant="normal">h</mi></mrow><mi mathvariant="normal">m</mi></mfrac><mfenced separators="|"><mrow><msub><mi mathvariant="normal">f</mi><mn>1</mn></msub><mo>-</mo><msub><mi mathvariant="normal">f</mi><mn>2</mn></msub></mrow></mfenced></mrow></mfenced><mfrac><mn>1</mn><mn>2</mn></mfrac></msup></math>