University of KashanIranian Journal of Mathematical Chemistry2228-648912420211201Extremal Cacti with respect to Sombor index19720811163210.22052/ijmc.2021.243026.1582ENHechaoLiuSchool of Mathematical Sciences, South China Normal University, Guangzhou, 510631, P. R. China0000-0001-7606-4842Journal Article20210821Recently, a novel topological index, Sombor index, was introduced by Gutman, defined as $SO(G)=\sum\limits_{uv\in E(G)}\sqrt{d_{u}^{2}+d_{v}^{2}}$, where $d_{u}$ denotes the degree of vertex $u$. In this paper, we first determine the maximum Sombor index among cacti with $n$ vertices and $t$ cycles, then determine the maximum Sombor index among cacti with perfect matchings. We also characterize corresponding maximum cacti.https://ijmc.kashanu.ac.ir/article_111632_de6f31ed2e636e86763d50333fb73e29.pdfUniversity of KashanIranian Journal of Mathematical Chemistry2228-648912420211201On Sombor Index and some Topological Indices20921511162410.22052/ijmc.2021.243137.1588ENChinglensanaPhanjoubamMathematics department, North-Eastern Hill University, Shillong, IndiaSainkupar MnMawiongDepartment of Basic Sciences and Social Sciences, North Eastern Hill University, Shillong, IndiaJournal Article20210927Gutman recently introduced a new vertex-degree-based topological index called the Sombor index. In this paper, we present some new results relating the Sombor index and some well-studied topological indices: Zagreb indices, forgotten index, harmonic index, (general) sum-connectivity index and symmetric division deg index.https://ijmc.kashanu.ac.ir/article_111624_70eb6680db0a7162341bf37cbe6de294.pdfUniversity of KashanIranian Journal of Mathematical Chemistry2228-648912420211201Topological Indices of a Kind of Altans21722411163310.22052/ijmc.2021.242983.1577ENShimaSalimiDepartment of Mathematics, University of Payame Noor, Tehran, IranAliIranmaneshTarbiat Modares UniversityJournal Article20210803Altans are a class of molecular graphs introduced recently. These graphs are attractive to many chemists and mathematicians. A topological index is a numerical invariant calculated for a description of molecular graphs. In this paper, we compute a few topological indices of Altans such as Wiener index, second Zagreb index, atom-bond connectivity (ABC) index, 〖ABC〗_4 index, etc.https://ijmc.kashanu.ac.ir/article_111633_13328fa0e939453c37f1689da4170b7a.pdfUniversity of KashanIranian Journal of Mathematical Chemistry2228-648912420211201The Randic Index of Trees with given Total Domination Number22523711163510.22052/ijmc.2021.243170.1591ENRoslanHasniSchool of Informatics and Applied Mathematics
Universiti Malaysia Terengganu
UMT Terengganu0000-0003-3695-2145Ayu Ameliatul ShahilahAhmad JamriUMT TerengganuNabeel EzzuldinArifTikrit UniversityFatimah NoorHarunUMT TerengganuJournal Article20211006Randi{\'c} index belongs to the most well-known topological indices in chemical graph theory. In this paper, we find upper bound for the Randi{\'c} index of trees in terms of the order and the total domination number. The extremal trees are characterized.https://ijmc.kashanu.ac.ir/article_111635_f818385c7fe7f8b5afb3d00ee3bf60a2.pdfUniversity of KashanIranian Journal of Mathematical Chemistry2228-648912420211201The effect of radial basis functions (RBFs) method in solving coupled Lane–Emden boundary value problems in Catalytic Diffusion Reactions23926111188110.22052/ijmc.2021.242232.1561ENAshrafHajiollowDepartment of Applied Mathematics‎, ‎Faculty of Mathematical Sciences‎, ‎University of Kashan‎, ‎Kashan‎,
‎87317-53153‎, ‎Iran.FatemehZabihiDepartment of Applied Mathematics‎, ‎Faculty of Mathematical Sciences‎, ‎University of Kashan‎, ‎Kashan‎,
‎87317-53153‎, ‎Iran.0000-0002-2449-4231Journal Article20210502In this paper, the radial basis functions (RBFs) method is applied to solve the coupled Lane–Emden boundary value problems arising in catalytic diffusion reactions. First, we multiply the equations by x to overcome the difficulties of the singularity at the origin. Then, the Kansa collocation method based on radial basis functions is used to approximate the unknown functions. By this technique, the problem with boundary conditions is reduced to a system of algebraic equations. We solve this system and compare the maximal residual error with the results previously, which show the presented method is efficient and produces very accurate and rapidly convergent numerical results in considerably low computational effort and easy implementation.https://ijmc.kashanu.ac.ir/article_111881_23ab896debd5533f18fa2da3bced2d57.pdf