Didid's zone-width and inradius conjecture

From papers

Let F4D0Z1,,ZnSd1F4D0\mathbf{Z}_1,\dots,\mathbf{Z}_n\subset \mathbb{S}^{d-1}, with d>2d>2, be zones of widths 2β1,,2βn2\beta_1,\dots,2\beta_n, respectively. Suppose that

Sd1(i=1nZi)\mathbb{S}^{d-1}\setminus\left(\bigcup_{i=1}^n\mathbf{Z}_i\right)

consists of 2m2m spherically convex open connected components with inradii F4D0γ1,,γ2mF4D0\gamma_1,\dots,\gamma_{2m}, respectively. Didid's conjecture. Then

2β1++2βn+γ1++γ2mπ.2\beta_1+\dots+2\beta_n+\gamma_1+\dots+\gamma_{2m}\geq\pi.

This is a generalization of the zone-covering theorem: it relates the total widths of the zones and the inradii of the complementary components. The supplied text attributes the problem to Didid through Polyanskii's account, but gives no resolution.

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Sources & referencesView supporting material

Primary source

Károly Bezdek and Zsolt Lángi, “On separability in discrete geometry”, arXiv:2407.20169 (2025).

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