Shahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901Energy of graphs12312887810.22061/jdma.2022.878ENMaryam Jalali-RadDepartment of pure math, University of KashanJournal Article20230724The energy, E(G), of a simple graph G is defined to be the sum of the absolute values of the eigen values of G. In this paper, we introduce some in-equalities of energy of graphs.https://jdma.sru.ac.ir/article_878_051dd89c60895d872c4ba6cd0254b7fe.pdfShahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901Eccentricity based indices for some classes fence graphs129135100210.22061/jdma.2022.1002ENK PattabiramanAnnamalai UniversityT SuganyaAnnamalai UniversityJournal Article20230722One of the most important ideas employed in chemical graph theory is that of so-called topological<br />indices. This is to associate a numerical value with a graph structure that often has some kind of<br />correlation with corresponding chemicals properties. In this paper, we consider some infinite<br />families of 3-fence graphs, namely, ladder, circular ladder and Mobius ladder. We compute some<br />of the eccentricity based topological indices of these graphs and their line graphs.https://jdma.sru.ac.ir/article_1002_0e39d14485ac0fee3eded17dbd1fa9a7.pdfShahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901Edge deletion and symmetric division degree index of graphs137145202510.22061/jdma.2023.9811.1053ENNajaf AmraeiDepartment of Mathematics, Shahid Rajaee Teacher Training University, Lavizan, 16785-163,
Tehran, I. R. Iran0000-0002-7918-9285Ali ZaeembashiJournal Article20230620The symmetric division deg index (or simply SDD) was proposed by Vukicevic et al.<br />as a remarkable predictor of total surface area of polychlorobiphenyls. We are interested in how the SDD of a graph changes when edges are deleted. The obtained results show that all cases are possible: increased, decreased and unchanged. In this article, we present some necessary conditions for the occurrence of each of the three different states.https://jdma.sru.ac.ir/article_2025_0c1f2e545ddadbc978fde2f03cdb251d.pdfShahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901The adjacency matrix of some hexagonal systems147155202710.22061/jdma.2023.10452.1064ENHasan BarzegarDepartment of mathematics, Tafresh university.Omid NekoeiJournal Article20230615The adjacency matrix is important invariant of a graph with a chemical meaning, when we study the chemical graphs. In this paper, the general form of the adjacency matrices of some hexagonal systems will be determined.https://jdma.sru.ac.ir/article_2027_1d0fa35afc5d880d8c2ade88a2fc87a4.pdfShahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901Power graphs via their characteristic polynomial157169203010.22061/jdma.2023.2030ENFatemeh Abbasi-BarfarazMinistry of Education, Organization for Education and Training, Tehran, I. R. IranJournal Article20230702A power graph is defined a graph that it's vertices are the elements of group and two vertices are adjacent if and only if one of them is a power of the other. Suppose $A(X)$ is the adjacency matrix of graph $X$. Then the polynomial $\chi(X,\lambda)=det(xI-A(X))$ is called as characteristic polynomial of $X$. In this paper, we compute the characteristic polynomial of all power graphs of order $p^2q$, where $p,q$ are distinct prime numbers.https://jdma.sru.ac.ir/article_2030_39e4fdfa377e5b71446d3586f5b6f219.pdfShahid Rajaee Teacher Training UniversityJournal of Discrete Mathematics and Its Applications2981-08098320230901Computing two types of geometric-arithmetic indices of some benzenoid graphs17117550710.22061/jmns.2015.507ENAmir LoghmanDepartment of Mathematics, Payame Noor UniversityMahboobeh SaheliDepartment of Mathematics, Yazd universityJournal Article20140802The geometric-arithmetic index is a topological index was defined as $GA(G)=\sum{uv\in E(G)}\frac{2\sqrt{d_ud_v}}{d_u+d_v}}$, where d<sub>u</sub> denotes the degree of vertex u in G. By replacing instead $\delta_u=\sum_{v\cong u} d_v$ of d<sub>u</sub> in GA(G), we have a new version of this index that defined as $GA(G)=\sum{uv\in E(G)}\frac{2\sqrt{\delta_u\delta_v}}{\delta_u+\delta_v}}$. In this paper, we present exact formulas of these indices for some benzenoid graphs.https://jdma.sru.ac.ir/article_507_2848ac7e8600a6dfeaa56f4376c0f83a.pdf