TY - JOUR
T1 - On the connection between energy and Zagreb indices of graphs
AU - Das, Kinkar Chandra
AU - Ghalavand, Ali
N1 - Publisher Copyright:
© The Author(s) under exclusive licence to Korean Society for Informatics and Computational Applied Mathematics 2025.
PY - 2025/6
Y1 - 2025/6
N2 - In our research, we are studying the relationship between the energy and Zagreb indices of a graph. We have proven several results, including: (i) tight lower and upper bounds for the energy of graphs based on their order, size, minimum degree, maximum degree, minimum eigenvalue, Zagreb indices, positive inertia, and negative inertia. We have also characterized the graphs that achieve equalities. (ii) Tight lower and upper bounds for maximum eigenvalue of graphs in terms of their order, size, minimum degree, maximum degree, and Zagreb indices. We have also characterized the graphs that achieve equalities. After conducting observations and computational calculations, we have formulated the conjecture that for a non-singular graph Ω with order p, size m, and the first Zagreb index M1(Ω), the following should hold: E(Ω)≥M1(Ω)m and E(Ω)≥M1(Ω)2m+2mp, with both equalities holding iff Ω≅Kp. It has been demonstrated that proving the first inequality will validate the second inequality.
AB - In our research, we are studying the relationship between the energy and Zagreb indices of a graph. We have proven several results, including: (i) tight lower and upper bounds for the energy of graphs based on their order, size, minimum degree, maximum degree, minimum eigenvalue, Zagreb indices, positive inertia, and negative inertia. We have also characterized the graphs that achieve equalities. (ii) Tight lower and upper bounds for maximum eigenvalue of graphs in terms of their order, size, minimum degree, maximum degree, and Zagreb indices. We have also characterized the graphs that achieve equalities. After conducting observations and computational calculations, we have formulated the conjecture that for a non-singular graph Ω with order p, size m, and the first Zagreb index M1(Ω), the following should hold: E(Ω)≥M1(Ω)m and E(Ω)≥M1(Ω)2m+2mp, with both equalities holding iff Ω≅Kp. It has been demonstrated that proving the first inequality will validate the second inequality.
KW - Adjacency matrix
KW - Degree
KW - Energy
KW - First Zagreb index
UR - https://www.scopus.com/pages/publications/85217237730
U2 - 10.1007/s12190-025-02376-5
DO - 10.1007/s12190-025-02376-5
M3 - Article
AN - SCOPUS:85217237730
SN - 1598-5865
VL - 71
SP - 3555
EP - 3575
JO - Journal of Applied Mathematics and Computing
JF - Journal of Applied Mathematics and Computing
IS - 3
ER -