Abstract
We prove that, for a finite ordered set P that contains no crowns with 6 or more elements, it can be determined in polynomial time if P has the fixed point property. This result is obtained by proving that every such ordered set must contain a point of rank 1 that has a unique lower cover or a retractable minimal element.
Similar content being viewed by others
References
Donalies, M., Schröder, B.: Performance guarantees and applications for Xia’s algorithm. Discret. Math. 213, 67–86 (2000) (Proceedings of the Banach Center Minisemester on Discrete Mathematics, week on Ordered Sets)
Duffus, D., Goddard, T.: The complexity of the fixed point property. Order 13, 209–218 (1996)
Felsner, S.: 3-interval irreducible partially ordered sets. Order 11, 97–125 (1994)
Fofanova, T., Rutkowski, A.: The fixed point property in ordered sets of width two. Order 4, 101–106 (1987)
Fofanova, T., Rival, I., Rutkowski, A.: Dimension 2, fixed points and dismantlable ordered sets. Order 13, 245–253 (1994)
Niederle, J.: Forbidden retracts for finite ordered sets of width at most four. Discrete Math. 308, 1774–1784 (2008)
Rival, I.: A fixed point theorem for finite partially ordered sets. J. Comb. Theory (A) 21, 309–318 (1976)
Schröder, B.: Fixed point property for 11-element sets. Order 10, 329–347 (1993)
Schröder, B.: Ordered Sets—an Introduction with Connections from Combinatorics to Topology, 2nd edn. Boston, Birkhäuser Verlag (2016)
Schröder, B.: The fixed point property for ordered sets of interval dimension 2. Order 34, 307–322 (2016)
Trotter, W. T.: Combinatorics and Partially Ordered Sets: Dimension Theory. Johns Hopkins University Press, Baltimore (1992)
Zaguia, I.: On the fixed point property for (3 + 1)-free ordered sets. Order 28, 465–479 (2011)
Acknowledgements
The author thanks the referees for constructive suggestions that improved and streamlined the presentation.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Schröder, B.S.W. Fixed Point Property for Finite Ordered Sets that Contain No Crowns with 6 or More Elements. Order 37, 173–178 (2020). https://doi.org/10.1007/s11083-019-09498-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11083-019-09498-z