Extrapolation, John-Nirenberg inequalities and characterizations of in terms of Morrey type spaces

We extend the extrapolation theory to Morrey spaces associated with Banach function spaces. Some applications by this theory such as the Fefferman-Stein vector-valued maximal inequalities are obtained. By using this extrapolation theory, we obtain the John-Nirenberg inequalities on Morrey spaces associated with Banach function spaces. In addition, by using the John-Nirenberg inequalities, we have the characterizations of the function spaces of bounded mean oscillation in terms of Morrey spaces associated with Banach function spaces.