Volume 211, Issue 5

This issue is a translation of Ukrains’kiĭ Matematychny ĭ Visnyk (Ukrainian Mathematical Bulletin) Vol. 12, No. 2, 2015. International Editorial Board of Ukrains’kiĭ Matematychnyĭ Visnyk: M. Atiyah, B. Bojarski, A. Friedman, O. Martio, L. Nirenberg, A. Samoilenko (Editor-in-Chief).