Results 61 to 70 of about 2,394 (219)

Connections between the matching and chromatic polynomials

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1992
The main results established are (i) a connection between the matching and chromatic polynomials and (ii) a formula for the matching polynomial of a general complement of a subgraph of a graph.
E. J. Farrell, Earl Glen Whitehead
doaj   +1 more source

Synergistic Multi‐Strategy Engineering of Temperature‐Responsive Self‐Trapped Excitons in Tin‐Based Double Perovskite Nanocrystals Enables High‐Sensitivity Fluorescence Thermometry

open access: yesLaser &Photonics Reviews, EarlyView.
Bi3+‐doped Cs2SnCl6 nanocrystals are engineered to deliver highly temperature‐responsive self‐trapped exciton emission, achieving record thermal sensitivity at elevated temperatures. A temperature‐induced dual‐STE excited state landscape enables reversible thermochromism, while a dual‐parameter calibration combining fluorescence lifetime and CIE‐y ...
Sujun Ji   +16 more
wiley   +1 more source

Colourings of (k-r,k)-trees [PDF]

open access: yesOpuscula Mathematica, 2017
Trees are generalized to a special kind of higher dimensional complexes known as \((j,k)\)-trees ([L. W. Beineke, R. E. Pippert, On the structure of \((m,n)\)-trees, Proc. 8th S-E Conf. Combinatorics, Graph Theory and Computing, 1977, 75-80]), and which
M. Borowiecki, H. P. Patil
doaj   +1 more source

New bounds for chromatic polynomials and chromatic roots

open access: yesDiscrete Mathematics, 2015
If $G$ is a $k$-chromatic graph of order $n$ then it is known that the chromatic polynomial of $G$, $π(G,x)$, is at most $x(x-1)\cdots (x-(k-1))x^{n-k} = (x)_{\downarrow k}x^{n-k}$ for every $x\in \mathbb{N}$. We improve here this bound by showing that \[ π(G,x) \leq (x)_{\downarrow k} (x-1)^{Δ(G)-k+1} x^{n-1-Δ(G)}\] for every $x\in \mathbb{N},$ where $
Jason I. Brown, Aysel Erey
openaire   +2 more sources

Evaluating anisotropy‐based Monin–Obukhov similarity theory over canopies and complex terrain

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
This study shows that an anisotropy‐based generalization of Monin–Obukhov surface‐layer scaling (SC23) applies readily across a wide range of atmospheric conditions with variable terrain, canopies, and land‐cover complexity. This work focuses on the scaling of velocity variances for 7 years at the 47 sites in the National Ecological Observation Network
Tyler S. Waterman   +3 more
wiley   +1 more source

A Symmetric Function of Increasing Forests

open access: yesForum of Mathematics, Sigma, 2021
For an indifference graph G, we define a symmetric function of increasing spanning forests of G. We prove that this symmetric function satisfies certain linear relations, which are also satisfied by the chromatic quasisymmetric function and unicellular $\
Alex Abreu, Antonio Nigro
doaj   +1 more source

Diffractive wavefront correction for Fe L‐edge spectroscopy on the meV scale

open access: yesJournal of Synchrotron Radiation, EarlyView.
We propose an aberration‐corrected, wavelength‐dispersive instrument for soft X‐ray spectroscopy at an energy‐resolving power of (5–6) × 104, designed for, for example, resonant inelastic X‐ray scattering at synchrotron beamlines or X‐ray free‐electron lasers.We propose a wavelength‐dispersive instrument for high‐resolution soft X‐ray spectroscopy at ...
Christoph Braig   +3 more
wiley   +1 more source

The multivariate arithmetic Tutte polynomial [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2012
We introduce an arithmetic version of the multivariate Tutte polynomial recently studied by Sokal, and a quasi-polynomial that interpolates between the two.
Petter Brändèn, Luca Moci
doaj   +1 more source

Cumulative heatwave stress disrupts thermal homeostasis and plumage structure in a Mediterranean passerine

open access: yesFunctional Ecology, EarlyView.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Heatwaves are becoming increasingly frequent across the Mediterranean and pose critical challenges for small passerines, yet the physiological and morphological limits to their resilience remain poorly understood.
Erick González‐Medina   +6 more
wiley   +1 more source

Roots of the Chromatic Polynomial [PDF]

open access: yes, 2017
The chromatic polynomial of a graph G is a univariate polynomial whose evaluation at any positive integer q enumerates the proper q-colourings of G.
Perrett, Thomas
core  

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