Almost contact metric hypersurfaces with type number 1 or 0 in nearly Kahlerian manifolds / M. B. Banaru. //Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2014. № 3. P. 60-62 [Moscow Univ. Math. Bulletin. Vol. 69, N 3, 2014.].
It is proved that for an almost contact metric hypersurface of nearly-Kahlerian manifold the condition for the type number to be equal to 1 or 0 is not only necessary but sufficient for this almost contact metric structure to be nearly cosymplectic.
Key words: almost contact metric structure, nearly cosymplectic structure, type number, hypersurface, nearly Kahlerian manifold.