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20122026
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7 papers · 1 filter

math.CO2026

Enumeration of Laplacian integral and {-1,0,1}-diagonalizable graphs

Nathaniel Johnston, Sarah Plosker, Luis M. B. Varona

A graph with Laplacian matrix is called Laplacian integral if the eigenvalues of are all integers, and it is called -diagonalizable if has a full set of eig…

math.CO2024

The Factor Width Rank of a Matrix

Nathaniel Johnston, Shirin Moein, Sarah Plosker

A matrix is said to have factor width at most if it can be written as a sum of positive semidefinite matrices that are non-zero only in a single principal submatri…

math.CO2023

Laplacian - and -diagonalizable graphs

Nathaniel Johnston, Sarah Plosker

A graph is called "Laplacian integral" if the eigenvalues of its Laplacian matrix are all integers. We investigate the subset of these graphs whose Laplacian is furthermore diagona…

math.CO2023

Weakly Hadamard diagonalizable graphs and Quantum State Transfer

Darian McLaren, Hermie Monterde, Sarah Plosker

Hadamard diagonalizable graphs are undirected graphs for which the corresponding Laplacian is diagonalizable by a Hadamard matrix. Such graphs have been studied in the context of q…

math.CO2020

Complex Hadamard Diagonalisable Graphs

Ada Chan, Shaun Fallat, Steve Kirkland +3

In light of recent interest in Hadamard diagonalisable graphs (graphs whose Laplacian matrix is diagonalisable by a Hadamard matrix), we generalise this notion from real to complex…

math.CO2019

Centrosymmetric Stochastic Matrices

Lei Cao, Darian McLaren, Sarah Plosker

We consider the convex set of stochastic matrices and the convex set of centrosymmetric stochastic matrices (stochastic…