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Estimates of covering type and minimal triangulations based on category weight

  • Dejan Govc , Wacław Marzantowicz and Petar Pavešić EMAIL logo
Published/Copyright: May 31, 2022

Abstract

In a recent publication [D. Govc, W. A. Marzantowicz and P. Pavešić, Estimates of covering type and the number of vertices of minimal triangulations, Discrete Comput. Geom. 63 2020, 1, 31–48], we have introduced a new method, based on the Lusternik–Schnirelmann category and the cohomology ring of a space X, that yields lower bounds for the size of a triangulation of X. In this current paper, we present an important extension that takes into account the fundamental group of X. In fact, if π1(X) contains elements of finite order, then one can often find cohomology classes of high ‘category weight’, which in turn allow for much stronger estimates of the size of triangulations of X. We develop several weighted estimates and then apply our method to compute explicit lower bounds for the size of triangulations of orbit spaces of cyclic group actions on a variety of spaces including products of spheres, Stiefel manifolds, Lie groups and highly-connected manifolds.


Communicated by Jan Bruinier


Award Identifier / Grant number: N1-0083

Award Identifier / Grant number: N1-0083

Award Identifier / Grant number: N1-0064

Funding source: Narodowe Centrum Nauki

Award Identifier / Grant number: UMO-2018/30/Q/ST1/00228

Funding statement: Dejan Govc was supported by the Slovenian Research Agency program P1-0292 and grant number N1-0083. Wacław Marzantowicz was supported by the Polish Research Grant NCN Sheng 1 UMO-2018/30/Q/ST1/00228. Petar Pavešić was supported by the Slovenian Research Agency program P1-0292 and grants numbers N1-0083, N1-0064.

Acknowledgements

The authors wish to express their thanks to Mahender Singh and Ergün Yalçin for helpful conversations on group actions on products of spheres and to John Oprea for his advice on the properties of category weight. We are also grateful to the anonymous referee whose comments led to several changes that considerably improved the readability of this paper.

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Received: 2021-08-22
Revised: 2022-01-20
Published Online: 2022-05-31
Published in Print: 2022-07-01

© 2022 Walter de Gruyter GmbH, Berlin/Boston

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