Results 31 to 40 of about 1,105 (90)

Effect of forced convection heat transfer over side-by-side square cylinders in a steady confined flow regime

open access: yes, 2016
A two-dimensional numerical study has been conducted to analyze forced convective confined flow and heat transfer from a pair of side-by-side square cylinders with a transverse gap ratio (defined as the ratio of the distance between the obstacles to the ...
A. Sanyal, A. Dhiman
semanticscholar   +1 more source

On the Minimum Number of Spanning Trees in Cubic Multigraphs

open access: yesDiscussiones Mathematicae Graph Theory, 2020
Let G2n, H2n be two non-isomorphic connected cubic multigraphs of order 2n with parallel edges permitted but without loops. Let t(G2n), t (H2n) denote the number of spanning trees in G2n, H2n, respectively. We prove that for n ≥ 3 there is the unique G2n
Bogdanowicz Zbigniew R.
doaj   +1 more source

Spectra of Orders for k-Regular Graphs of Girth g

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A (k, g)-graph is a k-regular graph of girth g. Given k ≥ 2 and g ≥ 3, infinitely many (k, g)-graphs of infinitely many orders are known to exist. Our goal, for given k and g, is the classification of all orders n for which a (k, g)-graph of order n ...
Jajcay Robert, Raiman Tom
doaj   +1 more source

Matchings Extend to Hamiltonian Cycles in 5-Cube

open access: yesDiscussiones 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

open access: yesDiscussiones 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

Forbidden Subgraphs for Existences of (Connected) 2-Factors of a Graph

open access: yesDiscussiones Mathematicae Graph Theory, 2023
Clearly, having a 2-factor in a graph is a necessary condition for a graph to be hamiltonian, while having an even factor in graph is a necessary condition for a graph to have a 2-factor.
Yang Xiaojing, Xiong Liming
doaj   +1 more source

A note on directed 4-cycles in digraphs [PDF]

open access: yes, 2012
Using some combinatorial techniques, in this note, it is proved that if $\alpha\geq 0.28866$, then any digraph on $n$ vertices with minimum outdegree at least $\alpha n$ contains a directed cycle of length at most ...
Liang, Hao, Xu, Jun-Ming
core  

Cyclic Cordial Labeling for the Lemniscate Graphs and Their Second Powers

open access: yesJournal of Mathematics, Volume 2025, Issue 1, 2025.
A lemniscate graph, usually denoted by Ln,m, is defined as a union of two cycles Cn and Cm that share a common vertex. A simple graph is called cyclic group cordial if we can provide a three elements’ cyclic group labeling satisfying certain conditions.
M. A. AbdAllah   +4 more
wiley   +1 more source

A Fan-Type Heavy Pair Of Subgraphs For Pancyclicity Of 2-Connected Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2016
Let G be a graph on n vertices and let H be a given graph. We say that G is pancyclic, if it contains cycles of all lengths from 3 up to n, and that it is H-f1-heavy, if for every induced subgraph K of G isomorphic to H and every two vertices u, v ∈ V (K)
Wideł Wojciech
doaj   +1 more source

The complete positivity of symmetric tridiagonal and pentadiagonal matrices

open access: yesSpecial 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

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