Results 31 to 40 of about 93 (56)
The complete positivity of symmetric tridiagonal and pentadiagonal matrices
Special Matrices, 2022 We provide a decomposition that is sufficient in showing when a symmetric tridiagonal matrix AA is completely positive. Our decomposition can be applied to a wide range of matrices.
Cao Lei, McLaren Darian, Plosker Sarah
doaj +1 more source
Dense Arbitrarily Partitionable Graphs
Discussiones Mathematicae Graph Theory, 2016 A graph G of order n is called arbitrarily partitionable (AP for short) if, for every sequence (n1, . . . , nk) of positive integers with n1 + ⋯ + nk = n, there exists a partition (V1, . . .
Kalinowski Rafał +3 more
doaj +1 more source
Some properties of the closed global shadow graphs and their zero forcing number
Acta Universitatis Sapientiae: Informatica, 2022 Zero forcing is one of the dynamic vertex coloring problem. Zero forcing number is the minimum cardinality of the zero forcing sets. This parameter is the upper bound for the maximum nullity. A new class of graph where the maximum nullity is equal to the
Raksha M. R., Dominic Charles
doaj +1 more source
Enumeration of weighted paths on a digraph and block hook determinant
Special Matrices, 2021 In this article, we evaluate determinants of “block hook” matrices, which are block matrices consist of hook matrices. In particular, we deduce that the determinant of a block hook matrix factorizes nicely.
Bera Sudip
doaj +1 more source
Matchings Extend to Hamiltonian Cycles in 5-Cube
Discussiones Mathematicae Graph Theory, 2018 Ruskey and Savage asked the following question: Does every matching in a hypercube Qn for n ≥ 2 extend to a Hamiltonian cycle of Qn? Fink confirmed that every perfect matching can be extended to a Hamiltonian cycle of Qn, thus solved Kreweras’ conjecture.
Wang Fan, Zhao Weisheng
doaj +1 more source
On q-Power Cycles in Cubic Graphs
Discussiones Mathematicae Graph Theory, 2017 In the context of a conjecture of Erdős and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e., with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic
Bensmail Julien
doaj +1 more source
A Note on Cycles in Locally Hamiltonian and Locally Hamilton-Connected Graphs
Discussiones Mathematicae Graph Theory, 2020 Let 𝒫 be a property of a graph. A graph G is said to be locally 𝒫, if the subgraph induced by the open neighbourhood of every vertex in G has property 𝒫. Ryjáček conjectures that every connected, locally connected graph is weakly pancyclic.
Tang Long, Vumar Elkin
doaj +1 more source
2-Spanning Cyclability Problems of Some Generalized Petersen Graphs
Discussiones Mathematicae Graph Theory, 2020 A graph G is called r-spanning cyclable if for every r distinct vertices v1, v2, . . . , vr of G, there exists r cycles C1, C2, . . . , Cr in G such that vi is on Ci for every i, and every vertex of G is on exactly one cycle Ci.
Yang Meng-Chien +3 more
doaj +1 more source
The Existence of Path-Factor Covered Graphs
Discussiones Mathematicae Graph Theory, 2023 A spanning subgraph H of a graph G is called a P≥k-factor of G if every component of H is isomorphic to a path of order at least k, where k ≥ 2. A graph G is called a P≥k-factor covered graph if there is a P≥k-factor of G covering e for any e ∈ E(G).
Dai Guowei
doaj +1 more source
Depth and Stanley depth of the edge ideals of the powers of paths and cycles
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2019 Let k be a positive integer. We compute depth and Stanley depth of the quotient ring of the edge ideal associated to the kth power of a path on n vertices.
Iqbal Zahid, Ishaq Muhammad
doaj +1 more source