Generally, all the models discussed so far are continuous time models. The continuous time models are quite apt at explaining the phenomena they are trying to predict and have known methods to get information from these type of models. But these models are not accurate for the physical systems which are observed over discreet time periods or which have non-continuous phenomena embedded in them, like production of new generation. Some species like salmon have non-overlapping generation characteristics since they have an annual spawning season and are born each year at a certain time. The discrete models are much more apt in describing the nature’s complex dynamics than the continuous models. A discrete-time modified Leslie-Gower system with double Allee effect is studied in this paper. The stability analysis of interior fixed points is performed. Using center manifold theorem it is shown that the system under consideration exhibits period-doubling and Neimark-Sacker bifurcations. The numerical simulations are provided to illustrate the consistency of the theoretical results.

We investigate the Sombor indices for a diverse group of nonsteroidal anti-inflammatory drugs (NSAIDs) to understand their molecular architecture and physicochemical properties. By utilizing quantitative structure-property relationship (QSPR) modeling, we establish mathematical models linking Sombor indices to key pharmacodynamic and toxicological parameters. Our study sheds light on how the molecular composition of NSAIDs influences their drug profiles and biological behavior, offering valuable insights for drug development and safety assessment.

In this paper, the relations of maximum degree energy and maximum reserve degree energy of a complete graph after removing a vertex have been shown to be proportional to the energy of the complete graph. The results of splitting the graph and shadow graphs are also presented for the complete graph after removing a vertex.

Based on the Hermitian adjacency matrices of second kind introduced by Mohar [1] and weighted adjacency matrices introduced in [2], we define a kind of index weighted Hermitian adjacency matrices of mixed graphs. In this paper we characterize the structure of mixed graphs which are cospectral to their underlying graphs, then we determine a upper bound on the spectral radius of mixed graphs with maximum degree \(\Delta\), and characterize the corresponding extremal graphs.

Modified group divisible designs MGD\((k, \lambda, m, n)\) are extensively studied because of an intriguing combinatorial structure that they possess and their applications. In this paper, we present a generalization of MGDs called GMGD\((k, \lambda_1, \lambda_2, m, n)\), and we provide some elementary results and constructions of some special cases of GMGDs. In addition, we show that the necessary conditions are sufficient for the existence of a GMGD\((3, \lambda, 2\lambda, m, n)\) for any positive integer \(\lambda\), and a GMGD\((3, 2, 3, m, n)\). Though not a general result, the construction of a GMGD\((3, 3, 2, 2, 6)\) given in the paper is worth mentioning in the abstract. Along with another example of a GMGD\((3, 3, 2, 2, 4)\), and \(n\) to \(tn\) construction, we have families of GMGD\((3, 3\lambda, 2\lambda, 2, n)\)s for \(n = 4t\) or \(6t\) when \(t \equiv 0, 1 \pmod 3\), for any positive integer \(\lambda\).

We show that connected, bicyclic graphs on nine edges with at least one cycle other than \(C_3\) decompose the complete graphs \(K_{18k}\) and \(K_{18k+1}\), for \(k\geq1\), when the necessary conditions allow for such a decomposition. This complements previous results by Freyberg, Froncek, Jeffries, Jensen, and Sailstad on connected bicyclic triangular graphs.

In the realm of graph theory, recent developments have introduced novel concepts, notably the \(\nu\varepsilon\)-degree and \(\varepsilon\nu\)-degree, offering expedited computations compared to traditional degree-based topological indices (TIs). These TIs serve as indispensable molecular descriptors for assessing chemical compound characteristics. This manuscript aims to meticulously compute a spectrum of TIs for silicon carbide \(SiC_{4}\)-\(I[r,s]\), with a specific focus on the \(\varepsilon\nu\)-degree Zagreb index, the \(\nu\varepsilon\)-degree Geometric-Arithmetic index, the \(\varepsilon\nu\)-degree Randić index, the \(\nu\varepsilon\)-degree Atom-bond connectivity index, the \(\nu\varepsilon\)-degree Harmonic index, and the \(\nu\varepsilon\)-degree Sum connectivity index. This study contributes to the ongoing advancement of graph theory applications in chemical compound analysis, elucidating the nuanced structural properties inherent in silicon carbide molecules.