Brazitikos–McIntyre conjecture on vector Maclaurin inequalities

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Let x1,x2,…,xn∈Rdx_1,x_2,\ldots,x_n\in\mathbb{R}^d be given with 1≤d≤n1\leq d\leq n. For p∈[0,∞]p\in[0,\infty] and 2≤k≤d2\leq k\leq d, consider the kk-fold exterior products xi1∧⋯∧xikx_{i_1}\wedge\cdots\wedge x_{i_k} and their Euclidean norms. Brazitikos–McIntyre conjecture. For every such pp and kk, one has

(∑1≤i1<⋯<ik≤n∣xi1∧⋯∧xik∣p(nk))1pk≤(∑1≤i1<⋯<ik−1≤n∣xi1∧⋯∧xik−1∣p(nk−1))1p(k−1),\left(\frac{\sum_{1\leq i_1<\cdots<i_k\leq n}|x_{i_1}\wedge\cdots\wedge x_{i_k}|^p}{\binom{n}{k}}\right)^{\frac{1}{pk}} \leq \left(\frac{\sum_{1\leq i_1<\cdots<i_{k-1}\leq n}|x_{i_1}\wedge\cdots\wedge x_{i_{k-1}}|^p}{\binom{n}{k-1}}\right)^{\frac{1}{p(k-1)}},

with equality if and only if n=dn=d and the vectors form an orthonormal basis. This extends Maclaurin's inequality from positive scalars to norms of exterior products of vectors; its status is not resolved by the supplied source information.

References

Primary source

Antal Joós and Zsolt Lángi, “Isoperimetric problems for zonotopes”, arXiv:2206.03204 (2023).

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