“…It is well known that, when studying the boundedness of some operators in the critical case, the weak Hardy space WH p (R n ) with p ∈ (0, 1] is a good substitute of the Hardy space H p (R n ) (see [5,6,13,16,23,28,31,40]). Moreover, the space WH p (R n ) was proved as the intermediate space in the real interpolation between the Hardy space H p (R n ) and the space L ∞ (R n ) (see [1,14,25,46]). Motivated by these, Yan et al [40] first introduced the variable weak Hardy spaces WH p(•) (R n ) via the radial grand maximal function and characterized these spaces by means of maximal functions, atoms, molecules and Littlewood-Paley functions.…”