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ℓ^p variant for 2 < p < ∞

Determine the sharp value or asymptotic behavior of β_{n,p} = max over A ∈ ℝ^{n×n} with unit ℓ2-norm rows of (1/2^n) ∑_{x∈{−1,1}^n} ||Ax||_p for 2 < p < ∞, and identify the extremal matrices that achieve it.

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Background

The paper fully resolves the cases p = 1 and p = 2 and establishes an upper bound of order c√p * n{1/p} for p > 2. However, the exact behavior for intermediate p remains unknown.

Thus the open problem is to determine tight bounds (or exact values) and extremizers for the ℓp version of the bad science matrix problem when 2 < p < ∞.

References

We note that the intermediate range $2 < p < \infty$ remains open but Theorem 6 gives an upper bound for the order of growth.

On the Structure of Bad Science Matrices (2408.00933 - Albors et al., 1 Aug 2024) in Subsection “ℓ^p variants.”