Superconvergence of a New Nonconforming Mixed Finite Element Scheme for Elliptic Problem

<table>The exact flux <svg height="13.825" id="M216" style="vertical-align:-4.0404pt" version="1.1" viewbox="0 0 17.575001 13.825" width="17.575001" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> (a) and numerical approximation <svg height="13.9625" id="M217" style="vertical-align:-4.15506pt" version="1.1" viewbox="0 0 23.7125 13.9625" width="23.7125" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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<g transform="matrix(.012,-0,0,-.012,11.175,13.762)"><path d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" id="x32"></path></g><g transform="matrix(.012,-0,0,-.012,16.886,13.762)"><path d="M499 88q-41 -46 -83.5 -73t-68.5 -27q-41 0 -19 98l52 225q10 43 8 59.5t-16 16.5q-37 0 -112 -65t-117 -135q-14 -42 -38 -179q-36 -7 -75 -20l-7 8l127 594q8 40 2.5 49t-35.5 9h-35l5 25q36 3 71.5 13t56.5 18t25 8q11 0 3 -38l-88 -417h2q77 102 195 167q44 24 79 24
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</svg> (b). </table>

Mathematical Problems in Engineering

fig2

Figure 2

Figure 2: Superconvergence of a New Nonconforming Mixed Finite Element Scheme for Elliptic Problem 