In this research, we discuss balancing two essential ecosystem services, known as resilience and yield, in a harvested two predators one prey system. We study how these two ecosystem services respond to different types of harvesting plans applied to the system. In individual harvesting, we observe that prey harvesting is suitable for generating more yield while either predator harvesting gives more

The aim of this paper is twofold: (a) to revisit the results in Iqbal et al. (Numer Algorithms 1–21, 2019. https:doi.org/10.1007/s11075-019-00854-z) and prove some convergence and stability results for the subclass of multivalued contractive operators under some mild conditions (b) to introduce a multivalued Reich-Suzuki type \(\alpha \)-nonexpansive mappings and present some fixed point results for

In order to study the impact of random environments during the spread of the disease, we propose a novel stochastic SIQS model on scale-free networks, which introduces stochastic perturbations to the infected rates. We first obtain the existence of global positive solutions. Moreover, by constructing appropriate stochastic Lyapunov functions, we prove sufficient conditions for extinction and persistence

Food-webs consisting of three or more species exhibit very complex dynamics in ecosystems which mainly depend on the various traits of prey and predator. In presence of predator, prey adopted optimal strategies to avoid predation and to increase their survival. The antipedator behaviour exhibited by prey against predator’s fear; have potential to change the qualitative dynamics of food web systems

In this paper, we consider an inverse source problem for a fractional pseudo-parabolic equation. We show that the problem is severely ill-posed (in the sense of Hadamard) and the Tikhonov regularization method is proposed to solve the problem. In addition, we present numerical examples to illustrate applicability and accuracy of the proposed method to some extent.

In this paper, we consider a two-predator–one-prey population model that incorporates both the inter-specific competition between two predator populations and the intra-specific competition within each predator population. We investigate the dynamics of this model by addressing the existence, local and global stability of equilibria, uniform persistence as well as saddle-node and Hopf bifurcations

Give a graph G, we color its all edges. If any two adjacent edges gets the different colors, then we call this color a proper edge coloring of G. Give a proper edge coloring of G, if only two colors alternately appear on a cycle, then the cycle is called bichromatic. Acyclic edge coloring of a graph G means that there are no bichromatic cycles in G. The acyclic chromatic index of a graph G is the minimum

Suppose \([3]=\{0,1,2,3\}\) and \([3^{-}]=\{-1,1,2,3\}\). An outer independent signed double Roman dominating function (OISDRDF) of a graph \(\Gamma \) is function \(l:V({\Gamma })\rightarrow [3^{-}]\) for which (i) each vertex t with \(l(t)=-1\) is joined to at least two vertices labeled a 2 or to at least one vertex z with \(l(z)=3\), (ii) each vertex t with \(l(t)=1\) is joined to at least a vertex

In this paper, a new conjugacy condition is established to solve unconstrained optimization problems based on a new quasi-Newton equation. We present a modified Dai–Liao conjugate gradient method to solve unconstrained optimization problems with a new value of the parameter t based on the new conjugacy condition. The presented algorithm has the following properties: (i) the modified Dai–Liao conjugate

In this paper, a Beddington-DeAngelis amensalism system with weak Allee effect on the first species are introduced and investigated. The existence and stability of all possible trivial, semi-trivial and interior equilibria of the model are studied. By utilizing Sotomayor’s theorem, bifurcation analysis has been proposed and obtain one saddle-node bifurcation. Furthermore, in view of Poincaré transformation

The purpose of this paper is to focus on continuous minimax problems with semi infinite constraints. We begin by proposing an algorithm for solving this kind of problems. The proposed algorithm combines the parametric approach and the Huard method of centers. That’s we extend the Method of Centers of Roubi for solving minimax fractional programs to continuous minimax problems. On the other hand, calculating

The explicit determinants, inverses and eigenpairs of periodic tridiagonal Toeplitz-like matrices with perturbed rows are presented in this paper. We derive the representation of the determinants and inverses in the form of products of Mersenne numbers and some initial values from matrix transformations, which reduces the computational complexity to a certain extent. Futhermore, we make some analysis

In this paper, two methods based on generalized successive overrelaxation (GSOR) for solving weakly nonlinear systems with complex coefficient matrices are proposed: Picard-accelerated GSOR (P-AGSOR) and Picard-preconditioned GSOR (P-PGSOR) methods. Theoretical analysis demonstrates the local convergence properties of the two methods under appropriate assumptions. Numerical examples confirm the effectiveness

The paper concerns with three iterative regularization methods for solving a variational inclusion problem of the sum of two operators, the one is maximally monotone and the another is monotone and Lipschitz continuous, in a Hilbert space. We first describe how to incorporate regularization terms in the methods of forward-backward types, and then establish the strong convergence of the resulting methods

To solve certain type of matrix equations and extend the notions of the Drazin-star and star-Drazin matrices, we define two new classes of rectangular matrices called the outer-star and star-outer matrices. We characterize these new matrices by algebraic and geometrical point of view and give properties of projectors determined by them. Various representations of outer-star and star-outer matrices

Networks of evolutionary processors (NEP for short) form a class of models within the new computational paradigms inspired by biological phenomena. They are known to be theoretically capable of solving intractable problems. So far, there are two main categories that differ from each other by the nature of filtering process controlling the communication step: random-context clauses or polarization.

n-Dimension quasi-twisted (QT) codes are generalizations of 2-dimension QT codes and n-dimension quasi-cyclic codes. In this paper, we study some structural properties of n-dimension QT codes of arbitrary length over finite fields including the decomposition, the trace representation and the minimum Hamming distance bound.

In this paper, new concepts of covering of fuzzy graphs are introduced. The definitions of fuzzy covering maps and fuzzy covering graphs of fuzzy graphs are given. Some special types of fuzzy covering graphs are discussed. Some important theorems to find out the fuzzy covering maps as well as fuzzy covering graphs for different types of fuzzy graphs are described. On the basis of the present situation

The objective of this paper is to introduce a method for constructing a minimal lattice-valued tree automaton with membership values in a totally ordered lattice (in short \(\mathcal {LTA}),\) based on the solvability of a system of fuzzy polynomial equations. Since the minimization problem strongly depends on the equivalence problem, at first, the equivalence problem is examined. For this purpose

In this paper, we classify all self-dual \(\lambda \)-constacyclic codes of length \(2^s\) over the finite commutative local ring \(R_{u^2, v^2,2^m}=\mathbb {F}_{2^m}[u,v]/\langle u^2, v^2, uv-vu \rangle \) corresponding to units of the forms \(\lambda =\alpha +\gamma v+\delta uv\), \(\alpha +\beta u+\delta uv\), \(\alpha +\beta u+\gamma v+\delta uv\), where \(\alpha ,\beta ,\gamma \in \mathbb {F}^*_{2^m}\)

In this paper, we investigate global behavior of the following max-type system of difference equations with four variables $$\begin{aligned} \left\{ \begin{array}{ll}x_{n} = \max \Big \{A,\frac{z_{n-1}}{y_{n-2}}\Big \},\\ y_{n} = \max \Big \{B ,\frac{w_{n-1}}{x_{n-2}}\Big \},\\ z_{n} = \max \Big \{C ,\frac{x_{n-1}}{w_{n-2}}\Big \},\\ w_{n} = \max \Big \{D,\frac{y_{n-1}}{z_{n-2}}\Big \},\\ \end{array}\right

In this paper, a numerical approximation is shown to solve solutions of time fractional linear differential equations of variable order in fluid mechanics where the considered fractional derivatives of variable order are in the Caputo sense. Existence, uniqueness of solutions and Ulam–Hyers stability results are displayed. To solve the considered equations a numerical approximation based on the shifted

In this paper, we study the structure of \({\mathbb {F}}_q\)-linear skew cyclic codes over \({\mathbb {F}}_{q^2}\). Some good \({\mathbb {F}}_q\)-linear skew cyclic codes over \({\mathbb {F}}_{q^2}\) are constructed. Moreover, as an application, some good quantum codes are obtained by \({\mathbb {F}}_q\)-linear skew cyclic codes over \({\mathbb {F}}_{q^2}\).

In this paper, a robust non standard numerical scheme has been analysed for singularly perturbed parabolic convection-diffusion problems with time delay. The numerical scheme comprises of implicit Euler method, Richardson extrapolation technique and non standard techniques developed by Mickens. Parameter uniform estimates for stability and consistency have been proved. Numerical experiments have been

In this paper, we study the variable-order (VO) time-fractional diffusion equations. For a VO function \(\alpha (t)\in (0,1)\), we develop an exponential-sum-approximation (ESA) technique to approach the VO Caputo fractional derivative. The ESA technique keeps both the quadrature exponents and the number of exponentials in the summation unchanged at different time level. Approximating parameters are

This study presents methods of hygiene and the use of masks to control the disease. The zero basic reproduction number can be achieved by taking the necessary precautionary measures that prevent the transmission of infection, especially from uninfected virus carriers. The existence of time delay in implementing the quarantine strategy and the threshold values of the time delay that keeping the stability

Cooperative hunting is a widespread phenomenon in the predator population which promotes the predation and the coexistence of the prey-predator system. On the other hand, the Allee effect among prey may drive the system to instability. In this work, we consider a prey-predator model with Type-III functional response involving the hunting cooperation in predator and Allee effect in the growth rate of

In this paper, we propose a new block Krylov-type subspace method for model reduction in large scale dynamical systems. We project the initial problem onto a new subspace, generated as a combination of rational and polynomial block Krylov subspaces. Simple algebraic properties are given and expressions of the error between the original and reduced transfer functions are established. Furthermore, we

This paper considers approximation methods to find common fixed points for two general nonlinear mappings that contain generalized hybrid mappings or normally 2-generalized hybrid mappings. First, we combine Nakajo and Takahashi’s hybrid method with a mean iteration method and prove three strong convergence theorems that approximate common fixed points for nonlinear mappings. We then develop Takahashi

In this work, the numerical approximation of the time-fractional mobile/immobile transport equation is considered. We investigate the solution regularity for two types of the initial data regularities. By applying the continuous piecewise linear finite elements in space, we obtain the spatial semidiscrete Galerkin scheme and derive its error estimates. We then propose two finite element schemes for

In this paper, we present a detailed description of the binomial theorem and obtain some new classes of combinatorial identities. As an application, we discuss a class of permutation binomials over finite fields \({\mathbb {F}}_q\), which is of the form \(x^{\mu +\nu }+2x^{\mu }\), where \(q\equiv 1\pmod {3}\) and \((\nu , q-1)=\frac{q-1}{3}\).

Entanglement-assisted quantum error-correcting codes (EAQECCs) provide a general framework for quantum code construction, which overcome certain self-orthogonal restriction. It becomes one main task in quantum error-correction to find EAQECCs with good parameters, especially entanglement-assisted quantum maximum distance separable (EAQMDS) codes. In this work, we construct four new families of EAQECC

In this article, we present a highly-accurate wavelet-based approximation to study and analyze the physical and numerical aspects of two-parameter singularly perturbed problems with Robin boundary conditions. To explore the swiftly changing behavior of such problems, we have used a special type of non-uniform mesh known as Shishkin mesh. Using Shishkin mesh with the Haar wavelet scheme contains a novelty

The main purpose of this paper is to develop a new method based on operational matrices of the linear cardinal B-spline (LCB-S) functions to numerically solve of the fractional stochastic integro-differential (FSI-D) equations. To reach this aim, LCB-S functions are introduced and their properties are considered, briefly. Then, the operational matrices based on LCB-S functions are constructed, for

Fuzzy graph theory provides tools for modeling different types of real-world networks. However, we should consider more relations, especially the relationship between edges with their corresponding vertices, which usually refer to incidences, when external factors influence the real flow in a network. Then, fuzzy incidence graphs may sometimes model certain real-world situations better. The present

For any \((1+u^2)\)-constacyclic code C with arbitrary length N over \(\mathbb {F}_2[u]/\langle u^3\rangle \), we construct a new map \(\Phi \) from \((\mathbb {F}_2[u]/\langle u^3\rangle )^{N}\) to \((\mathbb {F}_2[v]/\langle v^2\rangle )^{2N}\), and derive \(\Phi (C)\) by applying the map to each codeword of C. We find that C and its image \(\Phi (C)\) have the same homogeneous distance, and the

Transmission of a vertex v of a connected graph G is the sum of distances from v to all other vertices in G. Graph G is transmission irregular (TI) if no two of its vertices have the same transmission, and G is interval transmission irregular (ITI) if it is TI and the vertex transmissions of G form a sequence of consecutive integers. Here we give a positive answer to the question of Dobrynin [Appl

For a commutative ring R with unity (\(1\ne 0\)), the zero-divisor graph of R is a simple graph with vertices as elements of \(Z(R)^{*}=Z(R)\setminus \{ 0 \}\), where Z(R) is the set of zero-divisors of R and two distinct vertices are adjacent whenever their product is zero. An algorithm is presented to create a zero-divisor graph for the ring of Gaussian integers modulo \(2^{n}\) for \(n\ge 1\). The

In this paper, we propose a mathematical model to assess the impact of social media advertisements in combating the coronavirus pandemic in India. We assume that dissemination of awareness among susceptible individuals modifies public attitudes and behaviours towards this contagious disease which results in reducing the chance of contact with the coronavirus and hence decreasing the disease transmission

Recently, a novel topological invariant based on degrees of end-vertices of an edge in a graph was put forward. It was named Sombor index. The definition of the Sombor invariant suggests another, rather a geometric view onto graph edges. Here, the mathematical relations between the Sombor index and some other well-known degree-based descriptors are investigated. Then, a few results of Nordhaus–Gaddum-type

The aim of this paper is to present a monotone numerical method on uniform mesh for solving singularly perturbed three-point reaction–diffusion boundary value problems. Firstly, properties of the exact solution are analyzed. Difference schemes are established by the method of the integral identities with the appropriate quadrature rules with remainder terms in integral form. It is then proved that

Many iterative schemes have already been developed to solve the equilibrium problems, one of which is the most efficient two-step extragradient method. The objective of this research is to propose two new iterative methods with inertial effect to solve equilibrium problems. These iterative methods are based on an extra-gradient method and a Mann-type iterative method. Two strong convergence theorems

The competitive relationship among the objects of a system often show variation when it is examined relative to different aspects or attributes. Fuzzy soft theory allows parametrization in the problems with vague data, as it inherits the properties of a fuzzy set and soft set simultaneously. This feature of fuzzy soft theory influenced us to represent the variation in competition that appears among

Two new NCP-functions are constructed firstly in this paper. The main purpose is to accelerate the process of solution-finding for tensor complementarity problem, which is implemented by neural network methods based on the promising NCP-functions. Moreover, the stability properties of the proposed neural networks are achieved via some theoretics and properties of generalization for linear and nonlinear

For any prime p and positive integer m, let R be the finite commutative ring \({\mathbb {F}}_{p^m}+u{\mathbb {F}}_{p^m}+v{\mathbb {F}}_{p^m}+uv{\mathbb {F}}_{p^m}\), where\(u^2=0,v^2=0\) and \(uv=vu\). Let \(\lambda =\lambda _1+u\lambda _2+v\lambda _3+uv\lambda _4\) be a unit of R, where \(\lambda _1, \lambda _2,\lambda _3, \lambda _4 \in \mathbb F_{p^m}\) and \(\lambda _1\ne 0\). We know that \(\lambda

A stochastic epidemic model with infectivity rate in incubation period and homestead–isolation on the susceptible is developed with the aim of revealing the effect of stochastic white noise on the long time behavior. A good understanding of extinction and strong persistence in the mean of the disease is obtained. Also, we derive sufficient criteria for the existence of a unique ergodic stationary distribution

We use the epidemic threshold parameter, \({{\mathcal {R}}}_{0}\), and invariant rectangles to investigate the global asymptotic behavior of solutions of the density-dependent discrete-time SI epidemic model where the variables \(S_{n}\) and \(I_{n}\) represent the populations of susceptibles and infectives at time \(n = 0,1,\ldots \), respectively. The model features constant survival “probabilities”

This study provides a detailed exposition of in-hospital community-acquired methicillin-resistant S. aureus (CA-MRSA) which is a new strain of MRSA, and hospital-acquired methicillin-resistant S. aureus (HA-MRSA) employing Caputo fractional operator. These two strains of MRSA, referred to as staph, have been a serious problem in hospitals and it is known that they give rise to more deaths per year

Author overlooked corrections regarding Grant number and should correctly read as.

This work applies a novel geometric criterion for nonlinear autonomous differential equations developed by Lu and Lu (NARWA 36:20–43, 2017) to a nonlinear SEIVS epidemic model with temporary immunity and achieves its threshold dynamics. Specifically, global-stability problems for the SEIVS model of Cai and Li (AMM 33:2919–2926, 2009) are effectively solved. The corresponding optimal control system

Let q be an odd prime power, and denote by \({\mathbb {F}}_q\) the finite field with q elements. In this paper, we consider the ring \(R={\mathbb {F}}_q+u{\mathbb {F}}_q+v{\mathbb {F}}_q\), where \(u^2=u, v^2=v,uv=vu=0\) and study double circulant and double negacirculant codes over this ring. We first obtain the necessary and sufficient conditions for a double circulant code to be self-dual (resp

A non-local boundary value problem with Caputo fractional derivative of order \(1<\nu <2\) is considered in this article. A numerical method comprising of an upwind difference scheme which is used to approximate the convection term and an \(L_2\) approximation of Caputo fractional derivative on an uniform mesh is constructed. Error estimate is derived. Numerical results are presented which validate

Individuals living with HIV/AIDS are significantly at higher risk of infection with Salmonella Typhi. A deterministic nonlinear mathematical model that describes the co-infection dynamics of HIV and typhoid incorporating typhoid vaccine and treatment has been developed. The basic reproduction number for the co-infection model is computed. The co-infection model exhibits four steady states, namely,

To understand the effect of population pressure (demand of population for forestry trees and land) on the atmospheric level of carbon dioxide gas, a nonlinear model is formulated and analyzed. In formulating the model, four dynamical variables namely; concentration of carbon dioxide, human population, population pressure and forest biomass are considered. In the modeling process, it is assumed that

This paper focuses on the existence and uniqueness of solutions for certain types of fractional differential equations involving Riemann–Liouville derivative. The main results are obtained by some fixed point theorems in Sobolev space.

In this paper, we introduce a new matrix for a graph G in which i th row sum and i th column sum are both equal to neighbors degree sum of i th vertex and define a new variant of graph energy called neighbors degree sum energy \(E_{N} (G)\) of a graph G. The striking feature of this new matrix is that it is related with some well known degree based topological indices like Zagreb type indices, forgotten

In this research article, we introduce the notion of q-rung picture fuzzy graph structures (q-RPFGSs). Further, we present the concepts of \(S_{i}\)-strongly regular q-RPFGSs and \(S_{i}\)-uniform q-RPFGSs. We study \(S_{i}\)-bipartite q-RPFGSs and \(S_{i}\)-r-partite q-RPFGSs and investigate some useful results of their \(S_{i}\)-regularity. In addition, we discuss drug trafficking in particular region

Malaria is a life-threatening mosquito-borne disease. It is transmitted through the bite of an infected Anopheles mosquito. Malaria may be fatal if not treated promptly. Malaria is a major public health problem in India. Here we propose an SIRS model to study the transmission dynamics of malaria with saturated treatment. We assume that the mosquito population is growing logistically in the environment

The identifying code has been used to place objects in the sensor and wireless networks. For the vertex x of a graph G, suppose \(N_G[x]\) is a subset of V(G) containing x and all of its neighbors. Then \(C\subseteq V(G)\) is called an identifying code of G, if for two distinct vertices x and y of G, both \(C\cap N_G[x]\) and \(C\cap N_G[y]\) are nonempty and distinct. The watching system of a graph

The max–min rodeg (\({M\!m_{sde}}\)) index is a useful topological index in mathematical chemistry. Damir Vuki\(\check{\text {c}}\)evi\(\acute{\text {c}}\) studied the mathematical properties of the max–min rodeg index. In this paper, we determine the n-vertex trees with the second, the third and the fourth for \(n\ge 7\), and the fifth for \(n\ge 10\) minimum \(M\!m_{sde}\) indices, unicyclic graphs