arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1604.07595math.FA
收藏

关于尖锐的Bohnenblust-Hille常数

Towards sharp Bohnenblust--Hille constants

Daniel Pellegrino, Eduardo Teixeira

摘要:

研究了一类关于$m$ -线性形式的Bohnenblust-Hille型不等式中最佳常数的最优性问题.而germinal估计表明指数增长,在这项工作中,我们提供了强有力的证据的猜想,在经典的Bohnenblust-Hille不等式的尖锐常数是普遍有界的,无论$m$的值,以下简称为\textit{Universality Conjecture}。在我们的方法中,我们引入了熵和复杂性的概念,旨在某种程度上衡量这种优化问题的复杂性。我们表明,熵的概念是至关重要的连接到普适性猜想,例如,如果熵增长最多指数关于$m$,然后最佳常数的$m$ % -线性Bohnenblust-希勒不等式的实际标量确实是有界的普遍$m$。很可能熵确实随着$4^{m-1}$而增长,在这种情况下,我们证明了最佳常数正是$2^{1-\frac{1}{m}} $。在双线性情况下,$m=2$,我们表明,任何极值的Littlewood的$4/3$ -不等式有熵$4$和复杂性$2$,因此,我们能够分类的所有极值的问题。我们还证明了,对于任何混合$\left( \ell _{1},\ell _{2}\right) $ % -Littlewood不等式,熵都是指数增长的,并且这类不等式的锐常数恰好是$(\sqrt{2})^{m-1}$ .除了{熵和复杂性的概念},我们在这项工作中开发的方法决定性地使用了一系列强非对称的$m$ -线性形式,这对理论有进一步的影响,正如我们在这里解释的那样。

英文摘要:

We investigate the optimality problem associated with the best constants in a class of Bohnenblust--Hille type inequalities for $m$--linear forms. While germinal estimates indicated an exponential growth, in this work we provide strong evidences to the conjecture that the sharp constants in the classical Bohnenblust--Hille inequality are universally bounded, irrespectively of the value of $m$; hereafter referred as the \textit{Universality Conjecture}. In our approach, we introduce the {notions of entropy and complexity}, designed to measure, to some extent, the complexity of such optimization problems. We show that the notion of entropy is critically connected to the Universality Conjecture; for instance, that if the entropy grows at most exponentially with respect to $m$, then the optimal constants of the $m$% --linear Bohnenblust--Hille inequality for real scalars are indeed bounded universally in $m$. It is likely that indeed the entropy grows as $4^{m-1}$, and in this scenario, we show that the optimal constants are precisely $2^{1-\frac{1}{m}} $. In the bilinear case, $m=2$, we show that any extremum of the Littlewood's $4/3$-inequality has entropy $4$ and complexity $2$, and thus we are able to classify all extrema of the problem. We also prove that, for any mixed $\left( \ell _{1},\ell _{2}\right) $% --Littlewood inequality, the entropy do grow exponentially and the sharp constants for such a class of inequalities are precisely $(\sqrt{2})^{m-1}$. In addition to the {notions of entropy and complexity}, the approach we develop in this work makes decisive use of a family of strongly non-symmetric $m$--linear forms, which has further consequences to the theory, as we explain herein.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑