“…Nolan and Pollard [110] were the first to introduce the notion of uniform in bandwidth consistency for kernel density estimators and they applied empirical process methods in their study. In the series of papers, [11,18,19,20,21,23,28,30,45,52,53,56,61,62,105], the authors established uniform consistency results for such estimators, where h n varies within suitably chosen intervals indexed by n. U -statistics, first considered by [81] in connection with unbiased statistics, and formally introduced by [84]. The theory of Ustatistics and U -processes has received considerable attention in the last decades due to its great number of applications and usefulness for solving complex statistical problems.…”