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Global well-posedness in L2 for the periodic Benjamin-Ono equation
- American Journal of Mathematics
- Johns Hopkins University Press
- Volume 130, Number 3, June 2008
- pp. 635-683
- 10.1353/ajm.0.0001
- Article
- Additional Information
We prove that the Benjamin-Ono equation is globally well-posed in $ H^s({\Bbb T}) $ for $ s\ge 0 $. Moreover we show that the associated flow-map is Lipschitz on every bounded set of $ H^s_0({\Bbb T}) $, $s\ge 0$, and even real-analytic in this space for small times. This result is sharp in the sense that the flow-map (if it can be defined and coincides with the standard flow-map on $ {H}_0^\infty({\Bbb T}) $) cannot be of class $ C^{1+\alpha} $, $\alpha>0 $, from $ H_0^s({\Bbb T}) $ into $ H_0^s({\Bbb T}) $ as soon as $ s< 0 $.