1<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> 2 <mrow> 3 <msubsup> 4 <mi>P</mi> 5 <mrow> 6 <mi>l</mi> 7 <mo>+</mo> 8 <mn>1</mn> 9 </mrow> 10 <mi>m</mi> 11 </msubsup> 12 <mfenced> 13 <mrow> 14 <mi>x</mi> 15 </mrow> 16 </mfenced> 17 <mspace width="1em"/> 18 <mo>=</mo> 19 <mspace width="1em"/> 20 <mfrac> 21 <mrow> 22 <mfenced> 23 <mrow> 24 <mn>2</mn> 25 <mi>l</mi> 26 <mo>+</mo> 27 <mn>1</mn> 28 </mrow> 29 </mfenced> 30 <mi>x</mi> 31 <msubsup> 32 <mi>P</mi> 33 <mrow> 34 <mi>l</mi> 35 </mrow> 36 <mi>m</mi> 37 </msubsup> 38 <mfenced> 39 <mrow> 40 <mi>x</mi> 41 </mrow> 42 </mfenced> 43 <mo>−</mo> 44 <mfenced> 45 <mrow> 46 <mi>l</mi> 47 <mo>+</mo> 48 <mi>m</mi> 49 <mo>+</mo> 50 <mn>1</mn> 51 </mrow> 52 </mfenced> 53 <msubsup> 54 <mi>P</mi> 55 <mrow> 56 <mi>l</mi> 57 <mo>−</mo> 58 <mn>1</mn> 59 </mrow> 60 <mi>m</mi> 61 </msubsup> 62 <mfenced> 63 <mrow> 64 <mi>x</mi> 65 </mrow> 66 </mfenced> 67 </mrow> 68 <mfenced> 69 <mrow> 70 <mi>l</mi> 71 <mo>−</mo> 72 <mi>m</mi> 73 <mo>+</mo> 74 <mn>1</mn> 75 </mrow> 76 </mfenced> 77 </mfrac> 78 </mrow> 79</math> 80 81