Results 81 to 90 of about 1,320 (180)

A chromatic partition polynomial

open access: yesDiscrete Mathematics, 1998
Let \(|\pi|\) denote the number of blocks in a partition \(\pi\) of \([n]= \{1,2, \dots, n\}\). Let \(p=a_1 a_2 \dots a_n\) be a permutation of \([n]\). A descent block of \(p\) is a maximal decreasing continuance subword \(a_ia_{i+1} \dots a_j\) of \(p\). The \(n\)th Eulerian polynomial \(A_n(t)\) (for \(n=0,1,2,\dots)\) is defined by \[ \sum_{k\geq 0}
openaire   +2 more sources

Unusual Thermally Induced Blueshift and Emission Amplification of Mn2+ Ions Enable Filter‐Free Luminescent Thermal Imaging

open access: yesAdvanced Science, Volume 13, Issue 48, 28 August 2026.
ABSTRACT The shift from point‐based thermal sensing to filter‐free thermal imaging requires luminescent thermometers that exhibit pronounced and thermally driven spectral changes within spectral regions matching the sensitivity profiles of the red, green and blue (RGB) channels of a digital camera.
Y. Abe   +3 more
wiley   +1 more source

Hardware‐Attentive Programmable Fourier Ptychography Enables Task‐Adaptive Label‐Free Virtual Staining

open access: yesAdvanced Science, Volume 13, Issue 46, 17 August 2026.
Task‐adaptive programmable optics enables label‐free virtual staining through optical‐attention‐guided acquisition and reconstruction. By optimizing wavelength, illumination angle, exposure time, and imaging depth, the framework learns task‐relevant optical measurements, generating clinically interpretable virtual stains with improved fidelity, non ...
Tianyue He   +13 more
wiley   +1 more source

A Note on a Broken-Cycle Theorem for Hypergraphs

open access: yesDiscussiones Mathematicae Graph Theory, 2014
Whitney’s Broken-cycle Theorem states the chromatic polynomial of a graph as a sum over special edge subsets.
Trinks Martin
doaj   +1 more source

Chromatic Polynomials [PDF]

open access: yesTransactions of the American Mathematical Society, 1946
Birkhoff, George D., Lewis, D. C.
openaire   +2 more sources

Chromatic Polynomials Of Some (m,l)-Hyperwheels [PDF]

open access: yesComputer Science Journal of Moldova, 2014
In this paper, using a standard method of computing the chromatic polynomial of hypergraphs, we introduce a new reduction theorem which allows us to find explicit formulae for the chromatic polynomials of some (complete) non-uniform $(m,l)-$hyperwheels ...
Julian A. Allagan
doaj  

Chromatic polynomials of generalized trees

open access: yesDiscrete Mathematics, 1988
This short note surveys some recent results on chromatic polynomials of graphs built up in a treelike manner of q-cliques (yieldig q-trees) or of n-gons (n-gon-trees).
openaire   +2 more sources

Proof of a Chromatic Polynomial Conjecture

open access: yesJournal of Combinatorial Theory, Series B, 2000
Let \(P(G,\lambda)\) be the chromatic polynomial of a graph \(G\) (i.e., the number of mappings \(f\) from the vertex set of \(G\) to \(\{1,2,\dots, \lambda\}\) such that \(f(x)\neq f(y)\) whenever \(x\) and \(y\) are adjacent vertices in \(G\) if \(\lambda\) is a positive integer).
openaire   +1 more source

Hypergraphs with Pendant Paths are not Chromatically Unique

open access: yesDiscussiones Mathematicae Graph Theory, 2014
In this note it is shown that every hypergraph containing a pendant path of length at least 2 is not chromatically unique. The same conclusion holds for h-uniform r-quasi linear 3-cycle if r ≥ 2.
Tomescu Ioan
doaj   +1 more source

A generalization of the chromatic polynomial of a cycle [PDF]

open access: yesComputer Science Journal of Moldova, 2005
We prove that if an edge of a cycle on vertices is extended by adding vertices, then the the chromatic polynomial of such generalized cycle is: $$P(H_k,\lambda)=(\lambda-1)^n\sum_{i=0}^k \lambda^i+(-1)^n(\lambda-1).$$
Julian A. Allagan
doaj  

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