摘要
Year 2021 is special.It sees the renaissance of concept of phase and the birth of a phase theory for matters much beyond complex numbers and single-input single-output(SISO)linear timeinvariant(LTI)systems while we celebrate the 60 th birthday of Lei Guo,an exemplary research leader of our times.Here we give a short tutorial of the newly developed phase theory,as a birthday present.
基金
Hong Kong Research Grants Council under Grant No.16200619
National Natural Science Foundation of China under Grant No.62073003。
