  Let $\mathcal{SN}$ be the strong measure zero $\sigma$-ideal. We prove a
result providing bounds for $\mathrm{cof}(\mathcal{SN})$ which implies
Yorioka's characterization of the cofinality of the strong measure zero. In
addition, we use forcing matrix iterations to construct a model of ZFC that
satisfies
$\mathrm{add}(\mathcal{SN})=\mathrm{cov}(\mathcal{SN})<\mathrm{non}(\mathcal{SN})<\mathrm{cof}(\mathcal{SN})$.
