Abstract
We study Dohmen–Pönitz–Tittmann’s bivariate chromatic polynomial \(c_\Gamma (k,l)\) which counts all \((k+l)\)-colorings of a graph \(\Gamma \) such that adjacent vertices get different colors if they are \(\le k\). Our first contribution is an extension of \(c_\Gamma (k,l)\) to signed graphs, for which we obtain an inclusion–exclusion formula and several special evaluations giving rise, e.g., to polynomials that encode balanced subgraphs. Our second goal is to derive combinatorial reciprocity theorems for \(c_\Gamma (k,l)\) and its signed-graph analogues, reminiscent of Stanley’s reciprocity theorem linking chromatic polynomials to acyclic orientations.
Similar content being viewed by others
References
Averbouch, I., Godlin, B., Makowsky, J.A.: An extension of the bivariate polynomial. Eur. J. Combin. 31(1), 1–17 (2010)
Beck, M., Robins, S.: Computing the continuous discretely: integer-point enumeration in polyhedra. Undergraduate Texts in Mathematics. Springer, New York (2007) Electronically available at http://math.sfsu.edu/beck/ccd.html
Beck, M., Zaslavsky, T.: Inside-out polytopes. Adv. Math. 205(1), 134–162 (2006) arXiv:math.CO/0309330
Dohmen, K.: Closed-form expansions for the bivariate chromatic polynomial of paths and cycles. Preprint ( arXiv:1201.3886) (2012)
Dohmen, K., Pönitz, A., Tittmann, P.: A new two-variable generalization of the chromatic polynomial. Discrete Math. Theor. Comput. Sci. 6(1), 69–89 (2003) (electronic)
Ehrhart, E.: Sur les polyèdres rationnels homothétiques à \(n\) dimensions. C. R. Acad. Sci. Paris 254, 616–618 (1962)
Greene, C.: Acyclic orientations. In: Aigner, M. (ed) Higher Combinatorics, NATO Advanced Science Institutes Series C: Mathematical and Physical Sciences, vol. 31, pp. 65–68. Reidel, Dordrecht (1977)
Greene, C., Zaslavsky, T.: On the interpretation of Whitney numbers through arrangements of hyperplanes, zonotopes, non-Radon partitions, and orientations of graphs. Trans. Am. Math. Soc. 280(1), 97–126 (1983)
Hillar, C.J., Windfeldt, T.: Fibonacci identities and graph colorings. Fibonacci Quart. 46/47 (2008/09), no. 3, 220–224. arXiv:0805.0992
Stanley, R.P.: Acyclic orientations of graphs. Discrete Math. 5, 171–178 (1973)
Zaslavsky, T.: Signed graph coloring. Discrete Math. 39(2), 215–228 (1982)
Zaslavsky, T.: Signed graphs. Discrete Appl. Math. 4, 47–74 (1982). Erratum, Discrete Appl. Math. 5 (1983), 248
Zaslavsky, T.: Orientation of signed graphs. Eur. J. Combin. 12(4), 361–375 (1991)
Zaslavsky, T.: A mathematical bibliography of signed and gain graphs and allied areas. Electron. J. Combin. 5 (1998). Dynamic Surveys 8 (electronic). Electronically available at http://www.math.binghamton.edu/zaslav/Bsg/index.html
Author information
Authors and Affiliations
Corresponding author
Additional information
We thank the referees for helpful suggestions. This research was partially supported by the U. S. National Science Foundation through the grants DMS-1162638 (Beck) and DGE-0841164 (Hardin).
Rights and permissions
About this article
Cite this article
Beck, M., Hardin, M. A Bivariate Chromatic Polynomial for Signed Graphs. Graphs and Combinatorics 31, 1211–1221 (2015). https://doi.org/10.1007/s00373-014-1481-6
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00373-014-1481-6
Keywords
- Signed graph
- Bivariate chromatic polynomial
- Deletion–contraction
- Combinatorial reciprocity
- Acyclic orientation
- Graphic arrangement
- Inside-out polytope