Equivalence of Sofic $p$-Metric Mean Dimensions and a Tame-Metric Variational Formula
Let $Γ$ be a countable discrete sofic group acting by homeomorphisms on a compact metrizable space $X$ and $Σ$ a sofic approximation of $Γ$. We prove that for every $1\leq p<\infty$, the sofic $p$-metric mean dimension is equivalent to the sofic metric mean dimension, i.e there exists a common value $ D_Σ(X,Γ)\in\{-\infty\}\cup[0,+\infty]$ such that, $$D_Σ(X,Γ)=\mdim_{Σ,\mathrm M,p}(X,Γ) =\mdim_{Σ,\mathrm M,\infty}(X,Γ),$$ which answers a question of Hayes in \cite[Question 3]{Hayes}. Moreover, a tame-metric variational formula is established. That is for every $1\leq q\leq\infty$, $$D_Σ(X,Γ) =\inf_{ρ\in\mathcal T(X)} \underline{\mdim}_{Σ,q}(X,ρ), $$ where $\mathcal T(X)$ is the set of all compatible metrics on $X$ having tame growth of covering numbers.