Abstract:
An oriented connected closed manifold Mn is called a URC-manifold if for any oriented connected closed manifold Nn of the same dimension there exists a nonzero-degree mapping of a finite-fold covering ˆMn of Mn onto Nn. This condition is equivalent to the following: for any n-dimensional integral homology class of any topological space X, a multiple of it can be realized as the image of the fundamental class of a finite-fold covering ˆMn of Mn under a continuous mapping f:ˆMn→X. In 2007 the author gave a constructive proof of Thom's classical result that a multiple of any integral homology class can be realized as an image of the fundamental class of an oriented smooth manifold. This construction yields the existence of URC-manifolds of all dimensions. For an important class of manifolds, the so-called small covers of graph-associahedra corresponding to connected graphs, we prove that either they or their two-fold orientation coverings are URC-manifolds. In particular, we obtain that the two-fold covering of the small cover of the usual Stasheff associahedron is a URC-manifold. In dimensions 4 and higher, this manifold is simpler than all the previously known URC-manifolds.
Bibliography: 39 titles.
Keywords:
realization of cycles, domination relation, URC-manifold, small cover, graph-associahedron.