Volume 215, Issue 4

This issue is a translation of Vestnik Novosibirskogo Gosudarstvennogo Universiteta: Seriya Matematika, Mekhanika, Informatika (Herald of Novosibirsk State University: Series Mathematics, Mechanics, Informatics) edited by Sergey S. Goncharov, Vol. 15, No. 1-2, 2015. Translated into English and edited by Tamara Rozhkovskaya (rozhk@math.nsc.ru)