This document summarizes research on multi-numerology 5G new radio (NR) systems. It begins with an introduction comparing the flexibility of NR and LTE, noting that NR allows simultaneous use of multiple numerologies. Section II further describes differences in flexibility between NR and LTE regarding 3GPP standards. Section III then outlines potential research opportunities for improving multi-numerology systems, such as addressing interference between non-orthogonal numerologies. Finally, Section IV indicates that simulation results on inter-numerology interference will be presented as a function of guard allocation and parameters.