Results 51 to 60 of about 568,566 (214)

Ultimate chromatic polynomials

open access: yesDiscrete Mathematics, 1994
An approach to enumeration problems relying on the algebra of free abelian groups is outlined. The main application is a generalization of the chromatic polynomial of a simple graph \(G\) to the ``ultimate chromatic polynomial'', which lies in the free abelian group generated by the poset \(K(G)\) of contractions of \(G\), and which reduces to the ...
Nigel Ray, William Schmitt
openaire   +1 more source

Hecke algebra and quantum chromatic symmetric functions [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2012
We evaluate induced sign characters of $H_n(q)$ at certain elements of $H_n(q)$ and conjecture an interpretation for the resulting polynomials as generating functions for $P$-tableaux by a certain statistic.
Brittany Shelton, Mark Skandera
doaj   +1 more source

Macdonald Polynomials and Chromatic Quasisymmetric Functions [PDF]

open access: yesElectronic Journal of Combinatorics, 2017
We express the integral form Macdonald polynomials as a weighted sum of Shareshian and Wachs' chromatic quasisymmetric functions of certain graphs.
J. Haglund, A. Wilson
semanticscholar   +1 more source

Boundary Chromatic Polynomial [PDF]

open access: yesJournal of Statistical Physics, 2008
We consider proper colorings of planar graphs embedded in the annulus, such that vertices on one rim can take Q_s colors, while all remaining vertices can take Q colors. The corresponding chromatic polynomial is related to the partition function of a boundary loop model. Using results for the latter, the phase diagram of the coloring problem (with real
Jacobsen, Jesper Lykke, Saleur, Hubert
openaire   +3 more sources

An equivalent formulation of chromatic quasi-polynomials [PDF]

open access: yesDiscrete Mathematics, 2018
Given a central integral arrangement, the reduction of the arrangement modulo a positive integer q gives rise to a subgroup arrangement in Z q l . Kamiya et al.
T. Tran
semanticscholar   +1 more source

The limit of chromatic polynomials

open access: yesJournal of Combinatorial Theory, Series B, 1979
AbstractWe consider the large size limit of the number of q-colourings for three types of planar graph and obtain expansions for this limit in powers of (q − 1)−1. The methods used to derive and investigate these series are related to more general methods of investigating the Tutte polynomial used in theoretical physics.
D. Kim, Ian G. Enting
openaire   +1 more source

Color‐Pure Organic Luminophores: Characteristics, Definitions, Physical Basis and Fundamental Design Principles

open access: yesAngewandte Chemie, EarlyView.
Color‐pure all‐organic emitters, i.e., with narrow spectral characteristics, are intensively studied for high‐definition organic LEDs and multi‐color bioimaging. In order to guide targeted materials design, this educative review discusses spectral characteristics, proper definitions and units, and the physical basis of spectral broadening, to distill ...
Johannes Gierschner   +6 more
wiley   +2 more sources

The chromatic polynomial of a graph [PDF]

open access: yesPacific Journal of Mathematics, 1985
First, the author summarizes some known results on chromatical polynomials and sketches their proofs. Then he lists the chromatical polynomials of all graphs with fewer than seven vertices.
openaire   +2 more sources

Evaluations of Hecke algebra traces at Kazhdan-Lusztig basis elements [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2013
For irreducible characters $\{ \chi_q^{\lambda} | \lambda \vdash n\}$ and induced sign characters $\{\epsilon_q^{\lambda} | \lambda \vdash n\}$ of the Hecke algebra $H_n(q)$, and Kazhdan-Lusztig basis elements $C'_w(q)$ with $w$ avoiding the pattern 312,
Sam Clearman   +3 more
doaj   +1 more source

On Weak Chromatic Polynomials of Mixed Graphs [PDF]

open access: yesGraphs Comb., 2012
A mixed graph is a graph with directed edges, called arcs, and undirected edges. A k-coloring of the vertices is proper if colors from {1, 2, . . . , k} are assigned to each vertex such that u and v have different colors if uv is an edge, and the color ...
M. Beck   +4 more
semanticscholar   +1 more source

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