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{{Context|date=October 2009}} {{Context|date=October 2009}}
In ], '''Bochner's formula''' is a statement relating ] on a ] <math> (M, g) </math> to the ]. More specifically, if <math> u : M \rightarrow \mathbb{R} </math> is a harmonic function (i.e., <math> \triangle_g u = 0 </math>, where <math> \triangle_g </math> is the ] with respect to <math> g </math>), then In ], '''Bochner's formula''' is a statement relating ] on a ] <math> (M, g) </math> to the ]. More specifically, if <math> u : M \rightarrow \mathbb{R} </math> is a harmonic function (i.e., <math> \triangle_g u = 0 </math>, where <math> \triangle_g </math> is the ] with respect to <math> g </math>), then
:<math>

<math>
\triangle \frac{1}{2}|\nabla u| ^2 = |\nabla^2 u|^2 + \mbox{Ric}(\nabla u, \nabla u) \triangle \frac{1}{2}|\nabla u| ^2 = |\nabla^2 u|^2 + \mbox{Ric}(\nabla u, \nabla u)
</math>, </math>,

where <math> \nabla u </math> is the ] of <math>u</math> with respect to <math> g</math>. Bochner used this formula to prove the ]. where <math> \nabla u </math> is the ] of <math>u</math> with respect to <math> g</math>. Bochner used this formula to prove the ].



Revision as of 01:03, 19 October 2009

It has been suggested that this article be merged with Bochner identity. (Discuss) Proposed since February 2009.
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In mathematics, Bochner's formula is a statement relating harmonic functions on a Riemannian manifold ( M , g ) {\displaystyle (M,g)} to the Ricci curvature. More specifically, if u : M R {\displaystyle u:M\rightarrow \mathbb {R} } is a harmonic function (i.e., g u = 0 {\displaystyle \triangle _{g}u=0} , where g {\displaystyle \triangle _{g}} is the Laplacian with respect to g {\displaystyle g} ), then

1 2 | u | 2 = | 2 u | 2 + Ric ( u , u ) {\displaystyle \triangle {\frac {1}{2}}|\nabla u|^{2}=|\nabla ^{2}u|^{2}+{\mbox{Ric}}(\nabla u,\nabla u)} ,

where u {\displaystyle \nabla u} is the gradient of u {\displaystyle u} with respect to g {\displaystyle g} . Bochner used this formula to prove the Bochner vanishing theorem.

The Bochner formula is often proved using supersymmetry or Clifford algebra methods.

Variations and generalizations

See also


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