Wave front sets, local smoothing and Bourgain's circular maximal theorem
The authors consider the maximal operators associated with circular means in two dimensions and their corresponding maximal operators. They obtain a new proof of Bourgain's circular maximal theorem [cf. \textit{J. Bourgain}, J. Anal. Mat. 47, 69-85 (1986; Zbl 0626.42012)] as well as a sharpening of known regularity results for the wave equation.
scientific article; zbMATH DE number 90886