On $\gamma_{{\mathcal L}}$-capacities of Cantor sets

Let ${\mathcal L}$ be a homogeneous elliptic second-order differential operator in $\mathbb{R}^d$, $d\ge3$, with constant complex coefficients. In terms of capacities $\gamma_{{\mathcal L}}$, removable singularities of ${\rm L}^{\infty}$-bounded solutions of the equations ${\mathcal L}f=0$ are described. For Cantor sets in $\mathbb{R}^d$ we prove comparability of $\gamma_{{\mathcal L}}$ with classical harmonic capacities of the potential theory for all ${\mathcal L}$ and corresponding $d$.