Timeline for Integral of gradient of a function times a vector fields, null whatever the function, implies null divergence and tangential limits conditions
Current License: CC BY-SA 4.0
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| when toggle format | what | by | license | comment | |
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| Apr 22 at 12:24 | comment | added | Jochen Wengenroth | Use test functions $f\in \mathscr D(\mathring K)$ and apply the definition of the distributional partial derivatives: $0=\int \langle \nabla f, w\rangle= \sum\limits_{k=1}^N \int \partial_j f \, w_j = \int f \mathrm{div}(w)$ and conclude $w=0$ a.e. (by the fundamental lemma of variational calculus). | |
| S Apr 22 at 11:40 | review | First questions | |||
| Apr 22 at 12:43 | |||||
| S Apr 22 at 11:40 | history | asked | Oersted | CC BY-SA 4.0 |