Volume 256, Issue 2

This issue is a translation of Itogi Nauki i Tekhniki. Sovremennaya Matematika i Ee Prilozheniya. Tematicheskie Obzory (Progress in Science and Technology. Contemporary Mathematics and Its Applications. Thematic Surveys), Vol. 158, Proceedings of the Seminar on Algebra and Mathematical Logic of the Kazan (Volga Region) Federal University, 2018.