Results 71 to 80 of about 2,374 (146)
New sharp bounds for logarithmic mean and identric mean
, 2013 For x,y>0 with x≠y, let L=L(x,y), I=I(x,y), A=A(x,y), G=G(x,y), Ar=A1/r(xr,yr) denote the logarithmic mean, identric mean, arithmetic mean, geometric mean and r-order power mean, respectively. We find the best constant p,q>0 such that the inequalities
Zhen-Hang Yang
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Toeplitz nonnegative realization of spectra via companion matrices
Special Matrices, 2019 The nonnegative inverse eigenvalue problem (NIEP) is the problem of finding conditions for the existence of an n × n entrywise nonnegative matrix A with prescribed spectrum Λ = {λ1, . . ., λn}.
Collao Macarena +2 more
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On a graph of monogenic semigroups
, 2013 Let us consider the finite monogenic semigroup SM with zero having elements {x,x2,x3,…,xn}. There exists an undirected graph Γ(SM) associated with SM whose vertices are the non-zero elements x,x2,x3,…,xn and, f or 1≤i,j≤n, any two distinct vertices xi ...
K. Das, Nihat Akgünes, A. Cevik
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Construction of 4 x 4 symmetric stochastic matrices with given spectra
Open MathematicsThe symmetric stochastic inverse eigenvalue problem (SSIEP) asks which lists of real numbers occur as the spectra of symmetric stochastic matrices. When the cardinality of a list is 4, Kaddoura and Mourad provided a sufficient condition for SSIEP by a ...
Jung Jaewon, Kim Donggyun
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On the Yang-Baxter-like matrix equation for rank-two matrices
Open Mathematics, 2017 Let A = PQT, where P and Q are two n × 2 complex matrices of full column rank such that QTP is singular. We solve the quadratic matrix equation AXA = XAX.
Zhou Duanmei, Chen Guoliang, Ding Jiu
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EXTREMAL LAPLACIAN-ENERGY-LIKE INVARIANT OF GRAPHS WITH GIVEN MATCHING NUMBER ∗
, 2013 . Let G be a graph of order n with Laplacian spectrum µ 1 ≥ µ 2 ≥ ··· ≥ µ n . TheLaplacian-energy-like invariant of graph G, LEL for short, is defined as: LEL(G) = n P −1k=1 √µ k .
Kexiang Xu, K. Das
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On the Laplacian index of tadpole graphs
Special MatricesIn this article, we study the Laplacian index of tadpole graphs, which are unicyclic graphs formed by adding an edge between a cycle Ck{C}_{k} and a path Pn{P}_{n}.
Braga Rodrigo O., Veloso Bruno S.
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Improvements in the upper bounds for the spread of a matrix
, 2015 In this paper, we present some new upper bounds for the spread of a matrix. These bounds improve the previous results. In addition, one of these bounds can be up to the optimum.
Pingping Zhang, Hu Yang
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Some Observations on the Smallest Adjacency Eigenvalue of a Graph
Discussiones Mathematicae Graph Theory, 2020 In this paper, we discuss various connections between the smallest eigenvalue of the adjacency matrix of a graph and its structure. There are several techniques for obtaining upper bounds on the smallest eigenvalue, and some of them are based on Rayleigh
Cioabă Sebastian M. +2 more
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Families of graphs with maximum nullity equal to zero forcing number
Special Matrices, 2018 The maximum nullity of a simple graph G, denoted M(G), is the largest possible nullity over all symmetric real matrices whose ijth entry is nonzero exactly when fi, jg is an edge in G for i =6 j, and the iith entry is any real number.
Alameda Joseph S. +7 more
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