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相关论文: Regularities of Typical Sigma Index on Caterpillar…

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This study explores the irregularity properties of trees with prescribed degree sequences by analyzing two prominent topological indices: the Albertson index and the sigma index. With a particular emphasis on caterpillar trees -frequently…

组合数学 · 数学 2025-12-16 Jasem Hamoud , Alexey Belov Yakovlevich , Muaadh Almahalebi , Duaa Abdullah

In this paper, degree-based topological indices play a key role in the structural analysis of graphs in this paper and have significant uses in chemical graph theory. We investigate the connections between three such tree indices: the…

组合数学 · 数学 2026-03-10 Duaa Abdullah , Jasem Hamoud

In this paper, we provide the irregularity properties of trees with strong support vertex by analyzing two prominent topological indices: the Albertson index and the Sigma index. We further establish extremal bounds for both indices across…

组合数学 · 数学 2025-05-13 Jasem Hamoud , Duaa Abdullah

We establish sharp extremal bounds on the Albertson and Sigma irregularity indices for trees with prescribed degree sequences, with emphasis on caterpillar trees as key extremal configurations. New lower and upper bounds are derived in…

组合数学 · 数学 2026-03-12 Jasem Hamoud , Duaa Abdullah

In this paper, we presented a study of topological indices on trees, where we show a relationship with irregularity of Albertson index and minimum, maximum degrees $\delta,\Delta$ of graph $G$, where contribute vital roles in determining…

组合数学 · 数学 2025-11-26 Jasem Hamoud , Artem Kornosov

In this paper, we have studied bounds based on topological indicators, from which we selected Albertson index $\mathrm{irr}$ and the Sigma index $\sigma$. The Sigma index was defined through the following relationship: \[…

组合数学 · 数学 2025-06-16 Jasem Hamoud , Alexei Belov-Kanel , Duaa Abdullah

In chemical graph theory, caterpillar trees have been an appealing model to represent the molecular structures of benzenoid hydrocarbon. Meanwhile, topological index has been thought of as a powerful tool for modeling quantitative…

概率论 · 数学 2021-02-26 Panpan Zhang , Xiaojing Wang

A topological index reflects the physical, chemical and structural properties of a molecule, and its study has an important role in molecular topology, chemical graph theory and mathematical chemistry. It is a natural problem to…

组合数学 · 数学 2022-07-08 Rui Song , Qiongxiang Huang

This paper investigates topological indices for the greedy tree $\mathcal{T}_\mathscr{D}$ associated with a graphic degree sequence $\mathscr{D} = (d_1 \geqslant d_2 \geqslant \dots \geqslant d_n)$ of a tree. A fundamental challenge in the…

综合数学 · 数学 2026-02-05 Jasem Hamoud , Duaa Abdullah

In this paper, we investigate The relationship between the Albertson index and the first Zagreb index for trees. For a tree $T=(V,E)$ with $n=|V|$ vertices and $m=|E|$ edges, we provide several bounds and exact formulas for these two…

组合数学 · 数学 2025-06-03 Jasem Hamoud , Alexei Belov-Kanel , Duaa Abdullah

In this paper, we refer to a asymptotic degree sequence as $\mathscr{D}=(d_1,d_2,\dots,d_n)$. The examination of topological indices on trees gives us a general overview through bounds to find the maximum and minimum bounds which reflect…

组合数学 · 数学 2025-12-16 Jasem Hamoud , Duaa Abdullah

A semiregular tree is a tree where all non-pendant vertices have the same degree. Belardo et al. (MATCH Commun. Math. Chem. 61(2), pp. 503-515, 2009) have shown that among all semiregular trees with a fixed order and degree, a graph with…

组合数学 · 数学 2009-06-09 Tuerker Biyikoglu , Josef Leydold

The Sombor index, a degree-based topological descriptor introduced by Gutman in 2021, lacks closed-form expressions for complex hierarchical trees with multi-level pendant structures and nonuniform degree distributions, despite extensive…

综合数学 · 数学 2026-03-05 Jasem Hamoud

Topological indices are scientific details of graphs which represents its topology and of the most part graph invariant. In QSAR/QSPR, physico-chemical characteristics and topological indices, for example, atom bond connectivity (ABC) and…

组合数学 · 数学 2019-10-24 Haidar Ali , Farzana Kousar

A graph $G$ is said to be Hamiltonian if it contains a spanning cycle. In this work, we investigate the Hamiltonian completeness of certain classes of caterpillar graphs, which are trees with a central path to which all other vertices are…

The sigma index in graph theory refers to a measure of the degree differences between vertices in a graph. The goal is to determine the graphs that have the maximum sigma index within certain classes of graphs. Abdo, Dimitrov, and Gutman…

综合数学 · 数学 2024-05-10 Jasem Hamoud , Artem Kurnosov

In this paper, the investigates Adriatic indices, specifically the sum lordeg index where it defined as $SL(G) = \sum_{u \in V(G)} \deg_G(u) \sqrt{\ln \deg_G(u)}$ and the variable sum exdeg index $SEI_a(G)$ for $a>0$, $a\neq 1$. We present…

组合数学 · 数学 2025-08-07 Jasem Hamoud , Duaa Abdullah

In this paper, we establishe the extremal bounds of the topological indices -- Sigma index -- focusing on analyzing the sharp upper bounds and the lower bounds of the Sigma index, which is known $\sigma(G)=\sum_{uv\in…

组合数学 · 数学 2026-03-31 Jasem Hamoud , Duaa Abdullah

Using inequalities is a good way of studying topological indices. Chemical graph theory is one of the nontrivial applications of graph theory. In this paper, we examine and calculate another degree-based topological index for…

综合数学 · 数学 2021-12-21 Masoud Ghods , Zahra Rostami

(Im)balance indices can be used to quantify the (im)balance of trees by assigning numerical scores to them. An easy way to generate a new index is to construct a compound index, e.g., a linear combination of established indices. Two of the…

种群与进化 · 定量生物学 2026-04-20 Linda Knüver , Mareike Fischer
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