Abstract
We call a convex subsetN of a convexd-polytopeP⊂E d ak-nucleus ofP ifN meets everyk-face ofP, where 0<k<d. We note thatP has disjointk-nuclei if and only if there exists a hyperplane inE d which bisects the (relative) interior of everyk-face ofP, and that this is possible only if [d+2/2]≤k≤d−1. Our main results are that any convexd-polytope with at most 2d−1 vertices (d≥3) possesses disjoint (d−1)-nuclei and that 2d−1 is the largest possible number with this property. Furthermore, every convexd-polytope with at most 2d facets (d≥3) possesses disjoint (d−1)-nuclei, 2d cannot be replaced by 2d+2, and ford=3, six cannot be replaced by seven.
Similar content being viewed by others
References
Bezdek, A., Bezdek, K., Odor, T.: On a Caratheodory-type theorem. Preprint (1988).
Goodman, J. E., Pach, J.: Cell decomposition of polytopes by bending. Israel J. Math.64, 129–138 (1988).
Grünbaum, B.: Convex Polytopes. New York: Interscience. 1967.
Hovanski, A. G.: Hyperplane sections of polytopes, toric varieties and discrete groups in Lobachevsky space. Functional Anal. Appl.20, 50–61 (1986).
Kincses, J.: Convex hull representation of cut polytopes. Preprint (1988).
Kleinschmidt, P., Pachner, U.: Shadow-boundaries and cuts of convex polytopes. Mathematika27, 58–63 (1980).
Lovász, L.: Combinatorial Problems and Exercises. Amsterdam-New York-Oxford: North-Holland. p. 51, problem 7.22.
Shephard, G. C.: Sections and projections of convex polytopes. Mathematika19, 144–162 (1972).
Author information
Authors and Affiliations
Additional information
Partially supported by Hung. Nat. Found. for Sci. Research number 1238.
Partially supported by the Natural Sciences and Engineering Council of Canada.
Partially supported by N.S.F. grant number MCS-790251.
Rights and permissions
About this article
Cite this article
Bezdek, K., Bisztriczky, T. & Connelly, R. On hyperplanes and polytopes. Monatshefte für Mathematik 109, 39–48 (1990). https://doi.org/10.1007/BF01298851
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01298851