Trilinear Airy estimates: Difference between revisions

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The following trilinear estimates are known:
The following trilinear estimates are known:


* The 1/4 estimate [[Ta-p2]] on '''R'''<nowiki>:</nowiki>
* The 1/4 estimate [[Ta2001]] on '''R'''<nowiki>:</nowiki>


<center><math>
<center><math>
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The 1/4 is sharp [[KnPoVe1996]].We also have
The 1/4 is sharp [[KnPoVe1996]].We also have


<center><math>|| uvw ||_{-1/4, -5/12+} <~ || u ||_{-1/4, 7/12+} || v ||_{-1/4, 7/12+} || w ||_{-1/4, 7/12+}
<center><math>|| uvw ||_{-1/4, -5/12+} <~ || u ||_{-1/4, 7/12+} || v ||_{-1/4, 7/12+} || w ||_{-1/4, 7/12+};
</math></center>
</math></center>


<span class="GramE">see</span> [<span class="SpellE">Cv</span>-p].
see [Cv-p].


* The 1/2 estimate [[CoKeStTkTa-p3]] on '''T'''<nowiki>: if </nowiki><span class="SpellE">u,v,w</span> have mean zero, then
* The 1/2 estimate [[CoKeStTkTa-p3]] on '''T''': if <math>u,v,w</math> have mean zero, then


<center><math>|| (uvw)_x ||_{1/2, -1/2}  
<center><math>|| (uvw)_x ||_{1/2, -1/2}  
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The 1/2 is sharp [[KnPoVe1996]].
The 1/2 is sharp [[KnPoVe1996]].


* ''Remark''<nowiki>: the </nowiki><span class="SpellE">trilinear</span> estimate always needs one more derivative of regularity than the bilinear estimate; this is consistent with the heuristics from the Miura transform from <span class="SpellE">mKdV</span> to <span class="SpellE">KdV</span>.
* ''Remark'': the trilinear estimate always needs one more derivative of regularity than the bilinear estimate; this is consistent with the heuristics from the [[Miura transform]] from [[mKdV]] to [[KdV]].


[[Category:Estimates]]
[[Category:Estimates]]

Revision as of 19:38, 4 March 2007

Algebraic identity

Much of the trilinear estimate theory for Airy equation rests on (various permutations of) the following "four-wave resonance identity":

  • The key algebraic fact is (various permutations of)
whenever

Estimates

The following trilinear estimates are known:

The 1/4 is sharp KnPoVe1996.We also have

see [Cv-p].

  • The 1/2 estimate CoKeStTkTa-p3 on T: if have mean zero, then

The 1/2 is sharp KnPoVe1996.

  • Remark: the trilinear estimate always needs one more derivative of regularity than the bilinear estimate; this is consistent with the heuristics from the Miura transform from mKdV to KdV.