Аннотация:Groups with a topology that is in one way or another consistent with the algebraic structure are considered. Classical groups with topology -- topological, paratopological, semitopological, quasitopological groups. We also study other ways of matching topology and algebraic structure. The minimum requirement in this paper is that the group is a right semitopological group (such groups are often called right topological groups). Are studied when a group with topology is a topological group, research in this direction began with the work of Deane Montgomery and Robert Ellis. The (invariant) semi-neighborhoods of the diagonal are used as a means of study.