The closed1-forms with isolated zeros and closed recurrent curves on closed surfaces are considered. The theorem of realization of such closed 1-forms is proved.
В настоящей работе нами доказано, что среди всех римановых пространств постоянной секционной кривизны только трехмерные пространства имеют кручение, инвариантное относительно группы движений. Тензор кручения в этих ...
The linear fractional transformations from C to C are investigated. Necessary and sufficient conditions for a topological conjugacy of such trans-formations are obtained.
We consider functions on compact 3-manifolds with boundary without critical points and with less than 4 critical points of its restrictions on the boundary. Their topological classification is obtained.