Misplaced Pages

Bochner identity: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 15:04, 10 April 2014 editMonkbot (talk | contribs)Bots3,695,952 editsm References: Task 5: Fix CS1 deprecated coauthor parameter errors (bot trial)← Previous edit Revision as of 12:03, 30 May 2018 edit undo71.209.33.238 (talk) Statement of the result: Added linkTags: Mobile edit Mobile web editNext edit →
Line 2: Line 2:


==Statement of the result== ==Statement of the result==
Let ''M'' and ''N'' be Riemannian manifolds and let ''u''&nbsp;:&nbsp;''M''&nbsp;→&nbsp;''N'' be a harmonic map. Let d''u'' denote the derivative (pushforward) of ''u'', ∇ the ], Δ the ], Riem<sub>''N''</sub> the ] on ''N'' and Ric<sub>''M''</sub> the ] on ''M''. Then Let ''M'' and ''N'' be ]s and let ''u''&nbsp;:&nbsp;''M''&nbsp;→&nbsp;''N'' be a harmonic map. Let d''u'' denote the derivative (pushforward) of ''u'', ∇ the ], Δ the ], Riem<sub>''N''</sub> the ] on ''N'' and Ric<sub>''M''</sub> the ] on ''M''. Then


:<math>\frac12 \Delta \big( | \nabla u |^{2} \big) = \big| \nabla ( \mathrm{d} u ) \big|^{2} + \big\langle \mathrm{Ric}_{M} \nabla u, \nabla u \big\rangle - \big\langle \mathrm{Riem}_{N} (u) (\nabla u, \nabla u) \nabla u, \nabla u \big\rangle.</math> :<math>\frac12 \Delta \big( | \nabla u |^{2} \big) = \big| \nabla ( \mathrm{d} u ) \big|^{2} + \big\langle \mathrm{Ric}_{M} \nabla u, \nabla u \big\rangle - \big\langle \mathrm{Riem}_{N} (u) (\nabla u, \nabla u) \nabla u, \nabla u \big\rangle.</math>

Revision as of 12:03, 30 May 2018

In mathematics — specifically, differential geometry — the Bochner identity is an identity concerning harmonic maps between Riemannian manifolds. The identity is named after the American mathematician Salomon Bochner.

Statement of the result

Let M and N be Riemannian manifolds and let u : M → N be a harmonic map. Let du denote the derivative (pushforward) of u, ∇ the gradient, Δ the Laplace–Beltrami operator, RiemN the Riemann curvature tensor on N and RicM the Ricci curvature tensor on M. Then

1 2 Δ ( | u | 2 ) = | ( d u ) | 2 + R i c M u , u R i e m N ( u ) ( u , u ) u , u . {\displaystyle {\frac {1}{2}}\Delta {\big (}|\nabla u|^{2}{\big )}={\big |}\nabla (\mathrm {d} u){\big |}^{2}+{\big \langle }\mathrm {Ric} _{M}\nabla u,\nabla u{\big \rangle }-{\big \langle }\mathrm {Riem} _{N}(u)(\nabla u,\nabla u)\nabla u,\nabla u{\big \rangle }.}

See also

References

External links

Categories: