General independent-entry matrix norm conjecture

About 5 years old · traced to

Let (Xij)i,j≤n(X_{ij})_{i,j\leq n} be independent, mean-zero random variables satisfying ∥Xij∥2p≤α∥Xij∥p\|X_{ij}\|_{2p}\leq\alpha\|X_{ij}\|_p for every p≥1p\geq 1 and all i,j≤ni,j\leq n, with a fixed constant α≥1\alpha\geq 1 (condition (25) in the source). Write ∥⋅∥\|\cdot\| for the operator norm and ∥S∥p=(E∣S∣p)1/p\|S\|_p=({\mathbb E}|S|^p)^{1/p}.

General independent-entry matrix norm conjecture. Then

E∥(Xij)∥∼αmax⁡i(∑jEXij2)1/2+max⁡j(∑iEXij2)1/2+max⁡1≤k≤nmin⁡I⊂[n],∣I∣≤ksup⁡∥s∥2,∥t∥2≤1∥∑i,j∉IXijsitj∥log⁡(k+1).\begin{aligned} {\mathbb E}\|(X_{ij})\| \sim_{\alpha} &\max_{i}\left(\sum_{j} {\mathbb E} X_{ij}^2\right)^{1/2}+\max_{j}\left(\sum_{i} {\mathbb E} X_{ij}^2\right)^{1/2} \\ &+\max_{1\leq k\leq n}\min_{I\subset [n],|I|\leq k} \sup_{\|s\|_2,\|t\|_2\leq 1}\left\|\sum_{i,j\notin I}X_{ij}s_it_j\right\|_{\log (k+1)}. \end{aligned}

This is stated as a generalization of the Rademacher conjecture and would give a matching, up to constants depending on α\alpha, upper bound for the corresponding lower estimate.

References

Primary source

Rafał Latała and Witold Świątkowski, “Norms of Randomized Circulant Matrices”, arXiv:2106.03139 (2022).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.