Results 81 to 90 of about 1,406 (208)

MacMahon symmetric functions, the partition lattice, and young subgroups

open access: yes, 2001
A MacMahon symmetric function is a formal power series in a finite number of alphabets that is invariant under the diagonal action of the symmetric group. In this article, we show that the MacMahon symmetric functions are the generating functions for the
Rosas, Mercedes H.   +2 more
core   +1 more source

Fractional List Packing for Layered Graphs

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT The fractional list packing number χ ℓ • ( G ) ${\chi }_{\ell }^{\bullet }(G)$ of a graph G $G$ is a graph invariant that has recently arisen from the study of disjoint list‐colourings. It measures how large the lists of a list‐assignment L : V ( G ) → 2 N $L:V(G)\to {2}^{{\mathbb{N}}}$ need to be to ensure the existence of a “perfectly ...
Stijn Cambie, Wouter Cames van Batenburg
wiley   +1 more source

Orientations of Graphs With at Most One Directed Path Between Every Pair of Vertices

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT Given a graph G $G$, we say that an orientation D $D$ of G $G$ is a KT orientation if, for all u , v ∈ V ( D ) $u,v\in V(D)$, there is at most one directed path (in any direction) between u $u$ and v $v$. Graphs that admit such orientations have been used to construct graphs with large chromatic number and small clique number that served as ...
Barbora Dohnalová   +3 more
wiley   +1 more source

On Fork‐Free t‐Perfect Graphs

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT In an effort to understand the complexity of the maximum independent set problem, Chvátal introduced t‐perfect graphs. While a full characterization of this class remains open, important progress has been made for claw‐free graphs [Bruhn and Stein, Math. Program. 2012] and P 5 ${P}_{5}$‐free graphs [Bruhn and Fuchs, SIAM J. Discrete Math. 2017]
Yixin Cao, Shenghua Wang
wiley   +1 more source

Optical Skyrmions with Tunable or Reconfigurable Topology Using Spin‐Decoupled Metaoptics

open access: yesLaser &Photonics Reviews, EarlyView.
The work introduces advanced optical elements capable of generating and dynamically reconfiguring complex light patterns known as optical skyrmions. By precisely shaping light polarization at the nanoscale, a single engineered metasurface can generate and manipulate robust and tunable polarization textures in an efficient and scalable way.
Andrea Vogliardi   +5 more
wiley   +1 more source

A Symmetric Function Generalization of the Chromatic Polynomial of a Graph

open access: yesAdvances in Mathematics, 1995
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +2 more sources

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

Comb‐Driven Coherent Optical Transmitter for Scalable DWDM Interconnects

open access: yesLaser &Photonics Reviews, EarlyView.
A comb‐driven coherent optical transmitter on a Si/SiN platform enables scalable DWDM interconnects by integrating ultra‐compact microring‐assisted modulators and interleavers. High‐baud coherent signaling achieves 400 Gb/s per wavelength and >$>$1 Tb/s multi‐channel transmission, with projected >$>$10 Tb/s per fiber, offering a path toward energy ...
Alireza Geravand   +11 more
wiley   +1 more source

Fault Detection of Electric Motors via Symmetrized Dot Pattern‐Based Features

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT This study proposes a novel symmetrized dot pattern (SDP) approach using designed SDP‐based features, extracted from transformed vibration signals, for fault detection. These features describe the compactness, inclination, and shape of the “snowflake” diagram distributions.
Mario Spirto   +6 more
wiley   +1 more source

On Calculating the Chromatic Symmetric Function

open access: yes
This paper investigates methods for calculating the chromatic symmetric function (CSF) of a graph in chromatic-bases and the $m_λ$-basis. Our key contributions include a novel approach for calculating the CSF in chromatic-bases constructed from forests and an efficient method for determining the CSF in the $m_λ$-basis.
Mobaraki, Nima Amoei   +2 more
openaire   +2 more sources

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