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Timeline for A basic stability question

Current License: CC BY-SA 4.0

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Aug 22, 2018 at 15:23 history edited A random mathematician CC BY-SA 4.0
Improved the title, previous title did not accurately describe the question
Aug 16, 2018 at 21:48 vote accept A random mathematician
Aug 16, 2018 at 4:20 vote accept A random mathematician
Aug 16, 2018 at 20:27
Aug 15, 2018 at 18:14 answer added Willie Wong timeline score: 2
Aug 15, 2018 at 17:11 comment added Willie Wong The answer to which would still be "no" because you can replace $u, v$ by $\lambda u, \lambda v$. So you still need to fix a scale.
Aug 15, 2018 at 17:02 comment added Willie Wong If you are so happy to move goal posts, you may as well add that $\Omega$ is bounded (to rule out exterior of a ball), and that $|V_i| = 1$ (in fact, a fortiori if $V_i$ is the direction of the gradient of $\nabla u_i$, and $u_i$ is $C^1$, then $V_i \in C^0$). Fixing the size of $V_i$ gets rid of the scaling issue also. In fact, you might as well re-phrase your question as: let $u, v\in C^1(\Omega)$ be two functions that agree on $\partial\Omega$ with non-vanishing gradient. Can $\|u-v\|_{H^1}$ be bounded by $\| \nabla u / |\nabla u| - \nabla v / |\nabla v|\|_{L^2}$?
Aug 15, 2018 at 16:43 history edited A random mathematician CC BY-SA 4.0
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Aug 15, 2018 at 15:51 comment added A random mathematician I added the assumption $|V_i|>0$.
Aug 15, 2018 at 15:48 history edited A random mathematician CC BY-SA 4.0
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Aug 15, 2018 at 15:22 history edited A random mathematician CC BY-SA 4.0
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Aug 15, 2018 at 13:44 comment added Willie Wong Please be more thoughtful about tags going forward. Your PDE is obviously not linear (absolute value function is not linear). Your PDE is not elliptic (a fortiori since my answer below; but I don't see any reason for you to believe that it is elliptic to start with). There's no hard dependencies on function spaces, and I don't see any special function entering the discussion.
Aug 15, 2018 at 13:35 history edited Willie Wong
edited tags
Aug 15, 2018 at 13:35 answer added Willie Wong timeline score: 2
Aug 14, 2018 at 23:48 history asked A random mathematician CC BY-SA 4.0