English

Small covers of graph-associahedra and realization of cycles

Algebraic Topology 2024-05-21 v1 Combinatorics Geometric Topology

Abstract

An oriented connected closed manifold MnM^n is called a URC-manifold if for any oriented connected closed manifold NnN^n of the same dimension there exists a nonzero degree mapping of a finite-fold covering M^n\widehat{M}^n of MnM^n onto NnN^n. This condition is equivalent to the following: For any nn-dimensional integral homology class of any topological space XX, a multiple of it can be realized as the image of the fundamental class of a finite-fold covering M^n\widehat{M}^n of MnM^n under a continuous mapping f ⁣:M^nXf\colon \widehat{M}^n\to X. In 2007 the author gave a constructive proof of the classical result by Thom 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 previously known URC-manifolds.

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Cite

@article{arxiv.1611.01816,
  title  = {Small covers of graph-associahedra and realization of cycles},
  author = {Alexander A. Gaifullin},
  journal= {arXiv preprint arXiv:1611.01816},
  year   = {2024}
}

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29 pages