Title: Tezy dopovideĭ 4-oï Miz︠h︡narodnoï konferent︠s︡iï z heometriï i topolohiï = Tezisy dokladov 4-oĭ Mez︠h︡dunarodnoĭ konferent︠s︡ii po geometrii i topologii = Theses of the reports to the 4th International Conference on Geometry and Topology