English

Homology cycles in manifolds with locally standard torus actions

Algebraic Topology 2023-02-20 v2 Commutative Algebra Combinatorics

Abstract

Let XX be a 2n2n-manifold with a locally standard action of a compact torus TnT^n. If the free part of action is trivial and proper faces of the orbit space QQ are acyclic, then there are three types of homology classes in XX: (1) classes of face submanifolds; (2) kk-dimensional classes of QQ swept by actions of subtori of dimensions <k<k; (3) relative kk-classes of QQ modulo Q\partial Q swept by actions of subtori of dimensions k\geqslant k. The submodule of H(X)H_*(X) spanned by face classes is an ideal in H(X)H_*(X) with respect to the intersection product. It is isomorphic to (Z[SQ]/Θ)/W(\mathbb{Z}[S_Q]/\Theta)/W, where Z[SQ]\mathbb{Z}[S_Q] is the face ring of the Buchsbaum simplicial poset SQS_Q dual to QQ; Θ\Theta is the linear system of parameters determined by the characteristic function; and WW is a certain submodule, lying in the socle of Z[SQ]/Θ\mathbb{Z}[S_Q]/\Theta. Intersections of homology classes different from face submanifolds are described in terms of intersections on QQ and TnT^n.

Keywords

Cite

@article{arxiv.1502.01130,
  title  = {Homology cycles in manifolds with locally standard torus actions},
  author = {Anton Ayzenberg},
  journal= {arXiv preprint arXiv:1502.01130},
  year   = {2023}
}

Comments

25 pages, 3 figures. Minor correction in Lemma 3.3 and a calculations of Subsection 7.1