Prishlyak A. O.
Ukr. Mat. Zh. - 2016. - 68, № 1. - pp. 28-37
We prove an analog of the Morse theorem in the case where the critical point belongs to the boundary of an $n$-dimensional manifold and find the least number of critical points for the Morse functions defined on the surfaces whose critical points coincide with the critical points of their restriction to boundary.
Ukr. Mat. Zh. - 2009. - 61, № 11. - pp. 1455-1473
We investigate closed 1-forms with isolated zeros on surfaces with edge. A criterion for the topological equivalence of closed 1-forms is proved.
Ukr. Mat. Zh. - 2003. - 55, № 6. - pp. 799-805
We consider m-fields that are generalizations of the Morse–Smale vector fields for manifolds with boundary. We construct complete topological invariants of m-fields on surfaces and m-fields without closed trajectories on three-dimensional manifolds. We also prove criteria for the topological equivalence of m-fields.
Ukr. Mat. Zh. - 2002. - 54, № 4. - pp. 492-500
For the Morse–Smale vector fields with beh2 on three-dimensional manifolds, we construct complete topological invariants: diagram, minimal diagram, and recognizing graph. We prove a criterion for the topological equivalence of these vector fields.
Ukr. Mat. Zh. - 2000. - 52, № 10. - pp. 1421-1425
We investigate the conjugacy of Morse functions on closed surfaces. By using cellular decompositions of surfaces, we formulate a criterion for the conjugacy of Morse functions. We establish a criterion for the conjugacy of mappings into a circle with nondegenerate critical points.
Ukr. Mat. Zh. - 1999. - 51, № 4. - pp. 568–571
For three-dimensional manifolds with the structure of a combinatorial block complex, we construct an invariant that allows one to verify the existence of isomorphisms, between these manifolds. For complexes of small dimensionality, we solve the problem on the possibility of extending the isomorphisms of subcomplexes to those of complexes.
Ukr. Mat. Zh. - 1997. - 49, № 10. - pp. 1373–1384
Theorems on the existence of vector fields with given sets of indexes of isolated singular points are proved for the cases of closed manifolds, pairs of manifolds, manifolds with boundary, and gradient fields. It is proved that, on a two-dimensional manifold, an index of an isolated singular point of the gradient field is not greater than one.
Ukr. Mat. Zh. - 1997. - 49, № 9. - pp. 1230–1235
For some knots and links with respect to regular isotopy, we introduce a new invariant, which is a Laurent polynomial in three variables. The properties of this invariant are studied.