Timeline for A Characterization of Closed Ideals in $C^{\infty}(\mathbb{R}^n)$
Current License: CC BY-SA 3.0
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| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
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| Feb 18, 2015 at 9:39 | comment | added | Jochen Wengenroth | The standard references to this subject are Malgrange's book Ideals of differentiable functions and the one of Tougeron Ideaux de fonctions differentiables. In higher dimensions things become quite complicated: The function $f(x,y)=y^2 - \exp(-1/x^2)$ generates a closed ideal in $\mathscr E(\mathbb R^2)=C^\infty(\mathbb R^2)$ (i.e., $\lbrace fg: g\in\mathscr E(\mathbb R^2)\rbrace$ is closed) whereas $g(x,y)=y^2 + \exp(-1/x^2)$ does not (this is example 4.8 in Tougeron's book). | |
| Feb 18, 2015 at 5:57 | review | First posts | |||
| Feb 18, 2015 at 6:06 | |||||
| Feb 18, 2015 at 5:55 | history | asked | Alec Payne | CC BY-SA 3.0 |