Zikai Tang

activity

20122024

most citedOn a Conjecture of Randić Index and Graph Radius

2 citations · 5 across the 7 of their papers we have counts for

collaborators

8 papers

math.CO2024

Higher order invariants of a graph based on the path sequence

Yirong Cai, Zikai Tang, Hanyuan Deng

Let $G = (V, E)$ be a simple and connected graph. A $h$ -order invariant of $G$ based on the path sequence is defined from a set of real numbers $f (x_{0}, x_{1}, \dots, x_{h})$ as $^{h…

math.CO2022

Molecular trees with extremal values of the second Sombor index

Zikai Tang, Hanyuan Deng

A new geometric background of graph invariants was introduced by Gutman, of which the simplest is the second Sombor index $S O_{2}$ , defined as $SO_2=SO_2(G)=\sum_{uv\in E}\frac{|d^2_…

math.GM2022

Maximum zeroth-order general Randić index of orientations of cacti

Jiaxiang Yang, Hanyuan Deng, Zikai Tang +1

The zeroth-order general Randić index $R_{a + 1}^{0}$ of an $n$ -vertices oriented graph $D$ is equal to the sum of $(d_{u_{i}}^{+})^{a} + (d_{u_{j}}^{-})^{a}$ over all arcs $u_{i} u_{j}$ of $D$ …

math.CO2021★ 1 cited

On the vertex-degree based invariants of digraphs

Hanyuan Deng, Jiaxiang Yang, Zikai Tang +2

Let $D = (V, A)$ be a digraphs without isolated vertices. A vertex-degree based invariant $I (D)$ related to a real function $φ$ of $D$ is defined as a summation over all arcs, $I(D) =…

math.CO2021

Leap eccentric connectivity index of some graph operations with subdivided edges

Ling Song, Zikai Tang

The leap eccentric connectivity index of $G$ is defined as $L ξ^{C} (G) = v \in V (G) \sum d_{2} (v ∣ G) e (v ∣ G)$ where $d_{2} (v ∣ G)$ be the second degree of the vertex $v$ and $e (v ∣ G)$ be…

math.CO2021★ 2 cited

On the first three minimum Mostar indices of tree-like phenylenes

Hechao Liu, Lihua You, Hanlin Chen +1

Let $G = (V_{G}, E_{G})$ be a simple connected graph with its vertex set $V_{G}$ and edge set $E_{G}$ . The Mostar index $M o (G)$ was defined as $Mo(G)=\sum\limits_{e=uv\in E(G)}|n_{u…

math.CO2017

On the connective eccentricity index of two types of trees

Zikai Tang, Lingyao Jiang, Hanyuan Deng

The connective eccentricity index $ξ^{ce} = \sum_{u \in V} \frac{d ( u )}{ε ( u )}$ , where $ε (u)$ and $d (u)$ denote the eccentricity and the degree of the vertex $u$ ,…

math.CO2012★ 2 cited

On a Conjecture of Randić Index and Graph Radius

Hanyuan Deng, Zikai Tang, Jie Zhang

The Randić index $R (G)$ of a graph $G$ is defined as the sum of $(d_{i} d_{j})^{- 1/2}$ over all edges $v_{i} v_{j}$ of $G$ , where $d_{i}$ is the degree of the vertex $v_{i}$ in $G$ . The radius…