Results 41 to 50 of about 4,115 (305)

Maximum and minimum values of inverse degree and forgotten indices on the class of all unicyclic graphs

open access: yesAKCE International Journal of Graphs and Combinatorics, 2023
For a connected simple graph G, the inverse degree index and forgotten index are defined as [Formula: see text] and [Formula: see text] respectively, where [Formula: see text] denotes the degree of vertex u in G.
Mohammad Ali Manian   +2 more
doaj   +1 more source

Rational exponents in extremal graph theory [PDF]

open access: yes, 2016
Given a family of graphs H, the extremal number ex(n,H) is the largest m for which there exists a graph with n vertices and m edges containing no graph from the family H as a subgraph.
David Conlon   +6 more
core   +1 more source

On Acyclic Structures with Greatest First Gourava Invariant

open access: yesJournal of Chemistry, 2022
Let ξ be a simple connected graph. The first Gourava index of graph ξ is defined as GO1ξ=∑μη∈Eξdμ+dη+dμdη, where dμ indicates the degree of vertex μ.
Mariam Imtiaz   +4 more
doaj   +1 more source

An advance in infinite graph models for the analysis of transportation networks

open access: yesInternational Journal of Applied Mathematics and Computer Science, 2016
This paper extends to infinite graphs the most general extremal issues, which are problems of determining the maximum number of edges of a graph not containing a given subgraph.
Cera Martín, Fedriani Eugenio M.
doaj   +1 more source

Extremal graphs of multiplicative sum Zagreb index [PDF]

open access: yesNotes on Number Theory and Discrete Mathematics
The multiplicative sum Zagreb index, regarded as the multiplicative version of the first Zagreb index, is defined as the product of the degree sum over all pairs of adjacent vertices.
Chunlei Xu   +3 more
doaj   +1 more source

A Note on the Maximum Genus of Graphs with Diameter 4 [PDF]

open access: yes, 2007
Let G be a simple graph with diameter four, if G does not contain complete subgraph K3 of order ...
WeiLi, He, Xiang, Ren, Lin, Zhao
core   +1 more source

Proofs by Transformation in Extremal Graph Theory [PDF]

open access: yes, 2022
A graph is a mathematical model representing binary relationships between elements of a set. It is composed of two sets: the set of the elements called the vertices and a set of pairs of vertices called the edges.
Devillez, Gauvain
core  

Maximal tree and unicylic graph for Euler Sombor index with given diameter

open access: yesAKCE International Journal of Graphs and Combinatorics
The study of topological descriptors is essential for understanding the underlying structures of graphs and networks. Numerous numerical descriptors associated with graphs have been used to analyze their overall structure.
Zahid Raza   +3 more
doaj   +1 more source

P_{m}-saturated graphs with minimum size [PDF]

open access: yesOpuscula Mathematica, 2004
By \(P_m\) we denote a path of order \(m\). A graph \(G\) is said to be \(P_m\)-saturated if \(G\) has no subgraph isomorphic to \(P_m\) and adding any new edge to \(G\) creates a \(P_m\) in \(G\). In 1986 L. Kászonyi and Zs.
Aneta Dudek, A. Paweł Wojda
doaj  

Maximum Reciprocal Degree Resistance Distance Index of Unicyclic Graphs

open access: yesDiscrete Dynamics in Nature and Society, 2020
The reciprocal degree resistance distance index of a connected graph G is defined as RDRG=∑u,v⊆VGdGu+dGv/rGu,v, where rGu,v is the resistance distance between vertices u and v in G. Let Un denote the set of unicyclic graphs with n vertices.
Gai-Xiang Cai, Xing-Xing Li, Gui-Dong Yu
doaj   +1 more source

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