2026/07/18 by Sergii Myroshnychenko, Dmitry Ryabogin, Kateryna Tatarko +1
#math.MG #math.DG #math.FA
We prove an analogue of Grünbaum's inequality on the sphere. Let n ≥ 3 and let K be a convex body on \mathbb Sn-1⊂ \mathbb Rn with centroid at θ∈ \mathbb Sn-1. Then for any u∈ \mathbb Sn-1 that is orthogonal to θ we have σ(K∩ u+) ≥ (1-(1)/(n))n-1 σ(K), where σ denotes the spherical measure. The constant in this inequality is optimal.