Dimension-free estimates for covering functionals of simplices and $\ell_p$ balls

Abstract

We study \(Γ_{2^n}(K)\), the least positive number \(γ>0\) such that an \(n\)-dimensional convex body \(K\) can be covered by \(2^n\) translates of \(γK\). For \(n\)-simplices \(Δ_n\), we prove that \(Γ_{2^n}(Δ_n)\), as a sequence in \(n\), tends to \(1/2\). For the cross-polytope \(B_1^n\), we show that \(Γ_{2^n}(B_1^n)\leq5/6\) holds for all \(n\geq2\), and that \(\limsup_{n\to\infty}Γ_{2^n}(B_1^n)\leq0.641\cdots\). Finally, we prove the existence of a constant \(κ_*<1\) such that \(Γ_{2^n}(B_p^n)\leqκ_*\) for all \(n\geq2\) and all \(p\in[1,\infty]\).