ag-gipp/GoUldI

<math xmlns="http://www.w3.org/1998/Math/MathML"><mover accent="true"><msup><mfenced close=")" open="("><mrow><mi>Δ</mi><mi>H</mi></mrow></mfenced><mn>2</mn></msup><mo>¯</mo></mover><mo>=</mo><mfrac><mn>1</mn><mi>N</mi></mfrac><msubsup><mo>∑</mo><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mi>N</mi></msubsup><mfenced close="]" open="["><mrow><mfenced close="⟩" open="⟨"><mrow><msub><mi>ψ</mi><mi>i</mi></msub><mo>|</mo><msubsup><mi>H</mi><mi>i</mi><mn>2</mn></msubsup><mo>|</mo><msub><mi>ψ</mi><mi>i</mi></msub></mrow></mfenced><mo>-</mo><msup><mfenced close="⟩" open="⟨"><mrow><msub><mi>ψ</mi><mi>i</mi></msub><mo>|</mo><msub><mi>H</mi><mi>i</mi></msub><mo>|</mo><msub><mi>ψ</mi><mi>i</mi></msub></mrow></mfenced><mn>2</mn></msup></mrow></mfenced></math>