Timeline for Principal symbol for non-linear differential operators
Current License: CC BY-SA 3.0
5 events
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| Sep 20, 2017 at 10:34 | comment | added | Igor Khavkine | @ntor, Goldschmidt's article is rather dense but mostly self-contained, so the notation is introduced earlier in the article. For a bit more discussion of this point of view on PDEs, see the earlier question MO76620. Once you can read the notation, the definition you are looking for is the second displayed equation of $\S7$ in Goldschmidt. Note, as I have already mentioned, the symbol (space) $g_k$ refers to the kernel of what you defined as the symbol (map) $\sigma$. | |
| Sep 20, 2017 at 9:39 | comment | added | Peter Wildemann | Unfortunately I am not able to find the definition you are pointing towards in your reference. I am not very familiar with the language used there | |
| Sep 18, 2017 at 16:17 | comment | added | Igor Khavkine | @ntor, you mean other than it's an empirical fact? I would simply guess that this notion has so far found limited utility. | |
| Sep 18, 2017 at 15:57 | comment | added | Peter Wildemann | Can you state a reason why is not discussed usually? Is it not the standard tool of checking/defining ellipticity or hyperbolicity? | |
| Sep 18, 2017 at 7:37 | history | answered | Igor Khavkine | CC BY-SA 3.0 |