1<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> 2 <mrow> 3 <mtext>beta</mtext> 4 <mfenced> 5 <mrow> 6 <mi>a</mi> 7 <mo>,</mo> 8 <mi>b</mi> 9 </mrow> 10 </mfenced> 11 <mo>=</mo> 12 <mfrac> 13 <mfenced> 14 <mrow> 15 <mi>a</mi> 16 <mo>+</mo> 17 <mi>b</mi> 18 </mrow> 19 </mfenced> 20 <mi>b</mi> 21 </mfrac> 22 <mtext>beta</mtext> 23 <mfenced> 24 <mrow> 25 <mi>a</mi> 26 <mo>,</mo> 27 <mi>b</mi> 28 <mo>+</mo> 29 <mn>1</mn> 30 </mrow> 31 </mfenced> 32 </mrow> 33</math> 34 35