Pattern-equivariant homology

Walton, J. J. (2017) Pattern-equivariant homology. Algebraic and Geometric Topology, 17(3), pp. 1323-1373. (doi: 10.2140/agt.2017.17.1323)

Abstract

Pattern-equivariant (PE) cohomology is a well-established tool with which to interpret the Čech cohomology groups of a tiling space in a highly geometric way. We consider homology groups of PE infinite chains and establish Poincaré duality between the PE cohomology and PE homology. The Penrose kite and dart tilings are taken as our central running example; we show how through this formalism one may give highly approachable geometric descriptions of the generators of the Čech cohomology of their tiling space. These invariants are also considered in the context of rotational symmetry. Poincaré duality fails over integer coefficients for the “ePE homology groups” based upon chains which are PE with respect to orientation-preserving Euclidean motions between patches. As a result we construct a new invariant, which is of relevance to the cohomology of rotational tiling spaces. We present an efficient method of computation of the PE and ePE (co)homology groups for hierarchical tilings.

• Item Type: Articles
• Additional Information: This research was supported by EPSRC.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Walton, Dr Jamie
• Authors: Walton, J. J.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Algebraic and Geometric Topology
• Publisher: Mathematical Sciences Publishers
• ISSN: 1472-2747
• ISSN (Online): 1472-2739
• Copyright Holders: Copyright © 2017 The Author
• First Published: First published in Algebraic and Geometric Topology 17(3): 1323-1373
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

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