Notes on (regular) T3-reflections in the category of semitopological groups

In this paper, we give a unified internal description of Ti-reflection Ti(G) for a semitopological group G with the concepts of Ti-quotient subgroups (i∈{0,1,2}). We also give internal descriptions for the T3-reflection T3(G) and regular reflection Reg(G) of a semitopological group G, which solves some problems of M. Tkachenko.