BMO with respect to Banach function spaces

Andrei K. Lerner, Emiel Lorist, Sheldy Ombrosi

For every cube $Q\subset {\mathbb{R}}^n$ we let $X_Q$ be a quasi-Banach function space over $Q$ such that $\Vert {\chi }_Q{\Vert }_{X_Q}\simeq 1$, and for $X=\{X_Q\}$ define \begin{align*} \|f\|_…