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The modified circular restricted three-body problem is numerically investigated by exploring the effect of three-body interaction on the basins of convergence connected to the in-plane as well as out-of-plane equilibrium points. The evolution of the positions of the libration points and their stability are illustrated as a function of parameter k due to three-body interaction. It is observed that the number of equilibrium points strongly depends on the sign and the magnitude of the three-body interaction parameter and there exist at most seven libration points where four are non-collinear and three are collinear with the primaries. Moreover, in the Copenhagen case we have found seven collinear libration points. Moreover, the non-collinear as well as collinear libration points are stable for various combinations of mass parameter μ and k. The collinear as well as non-collinear libration points are stable for even those values of μ which are higher than the μ crit of the classical restricted three-body problem. The study of the regions of possible motion shows that as the value of the Jacobian constant decreases, the forbidden region decreases significantly. The attracting domains of the basins of convergence, on several types of two-dimensional planes, are unveiled by applying the multivariate Newton-Raphson iterative scheme. In an attempt to analyse the effect of parameter k on the topology of basins of convergence, a systematic and thorough investigations are presented. The degree of fractality is also unveiled by determining the basin entropy of the convergence plane. • The restricted three-body problem with additional effect of three-body interaction is discussed. • The existence and stability of libration points are discussed. • We numerically investigated the topology of BoCs. • The basin entropy S_b as function of three-body interaction parameter are unveiled. [ABSTRACT FROM AUTHOR]

The analysis of the affect of angular velocity on the geometry of the basins of convergence (BoC) linked to the equilibrium points in the restricted three-body problem is illustrated when the primaries are source of radiation. The bivariate scheme of the Newton–Raphson (N–R) iterative method has been used to discuss the topology of the basins of convergence. The parametric evolution of the fractality of the convergence plane is also presented where the degree of fractality is illustrated by evaluating the basin entropy of the convergence plane. • The perturbed restricted three-body problem has been studied. • Existence of the libration points are discussed, as a function of the angular velocity. • We unveil the Newton–Raphson basins of convergence, linked with the libration points. • Basin entropy as function of angular velocity and radiation parameter are illustrated. [ABSTRACT FROM AUTHOR]

In this paper, a HIV/AIDS and TB co-infection model has been explored, which incorporates detection and treatment for both diseases. We begin with presenting a co-infection model and then start analyzing both the HIV and the TB sub-models separately. The basic reproduction numbers corresponding to both HIV and TB are computed. Both the HIV/AIDS and the TB sub-models have been shown to exhibit two equilibrium points, namely, the disease-free equilibrium point and the unique endemic equilibrium point. For both sub-models, the disease-free equilibrium point is locally as well as globally asymptotically stable when their corresponding reproduction number is less than unity. The endemic equilibrium point for both sub-models exists, when their corresponding reproduction numbers is greater than one. We also analyze the full HIV-TB co-infection model. With the aim of minimizing infectives and the cost of applying effort towards the detection and the treatment, optimal control analysis is performed for the full model using the Pontryagin's maximum principle. Numerical simulations with different combinations of efforts are then performed to explore the effect of detection in the presence of treatment for both diseases. Numerical simulations emphasize the fact that to reduce co-infection from the population, programs to accelerate the detection of both diseases are also required along with the treatment. • This paper presents a non-linear HIV-TB co-infection model. • Local stability analysis for the model has been done. • An optimal control problem to minimize the total cost is presented. • The existence and characterization of the optimal controls has been established. [ABSTRACT FROM AUTHOR]

• The axisymmetric restricted five-body problem within the frame of variable mass has been studied. • The positions of libration points are illustrated. • The basins of convergence are unveiled. • The basin entropy is presented. The present manuscript reveals the existence and stability of the libration points (LPs) in the axisymmetric restricted five-body problem (AR5BP) in which mass of the fifth particle varies with respect to time as per Jeans' law. It has been assumed that the four bodies P i with masses m i , i = 1 , 2 , ... , 4 (when m 3 = m 4 = m ˜) form an axisymmetric convex configuration. The system of differential equations which govern the motion of the test particle (whose mass is variable) moving under the gravitational influence of the four primaries, have been presented, indeed, these equations are different from those of the test particle with constant mass in the AR5BP. We have determined the in-plane and out-of-plane LPs along with their linear stability. Furthermore, it is observed that the existence of these LPs depends not only on the angle parameters α and β but also on the parameters occur due to variation in mass namely γ (0 < γ ≤ 1) and σ (0 ≤ σ ≤ 2.2 , a proportionality constant occurs in Jeans' law). Moreover, we have investigated the evolution of the regions of possible motion as function of variable mass parameters where the fifth body can move freely. The topology of the basins of convergence (BoC) linked with the LPs as function of σ is unveiled by deploying the bivariate version of Newton-Raphson (NR) iterative method, and, in order to measure the uncertainty of the basins, the basin entropy is also evaluated. The co-relations between the domains of basins of convergence (DoBoC) and the required number of iterations to achieve predefined accuracy, and also with the corresponding probability distributions are illustrated. [ABSTRACT FROM AUTHOR]

The axisymmetric restricted five-body problem with the concave configuration has been studied numerically to reveal the basins of convergence, by exploring the Newton–Raphson iterative scheme, corresponding to the coplanar libration points (which act as attractors). In addition, four primaries are set in axisymmetric central configurations introduced by Érdi and Czirják [13] and the motion is governed by mutual gravitational attraction only. The evolution of the positions of libration points is illustrated, as a function of the value of angle parameters. A systematic and rigorous investigation is performed in an effort to unveil how the angle parameters affect the topology of the basins of convergence. In addition, the relation of the domain of basins of convergence with required number of iterations and the corresponding probability distributions are illustrated. • The axisymmetric restricted five-body problem: the concave case has been studied. • The locations of the libration points and their stability have been discussed. • The basins of convergence associated with libration points are discussed by using Newton–Raphson iterative scheme. [ABSTRACT FROM AUTHOR]

Abstract In the present work, the Newton–Raphson basins of convergence, corresponding to the coplanar libration points (which act as numerical attractors), are unveiled in the axisymmetric five-body problem, where convex configuration is considered. In particular, the four primaries are set in axisymmetric central configuration, where the motion is governed only by mutual gravitational attractions. It is observed that the total number libration points are either eleven, thirteen or fifteen for different combinations of the angle parameters. Moreover, the stability analysis revealed that all the libration points are linearly stable for all the studied combination of angle parameters. The multivariate version of the Newton–Raphson iterative scheme is used to reveal the structures of the basins of convergence, associated with the libration points, on various types of two-dimensional configuration planes. In addition, we present how the basins of convergence are related with the corresponding number of required iterations. It is unveiled that in almost every case, the basins of convergence corresponding to the collinear libration point L 2 have infinite extent. Moreover, for some combination of the angle parameters, the other collinear libration points L 1 , 2 also have infinite extent. In addition, it can be observed that the domains of convergence, associated with the collinear libration point L 1 , look like exotic bugs with many legs and antennas whereas the domains of convergence, associated with L 4 , 5 look like butterfly wings for some combinations of angle parameters. Particularly, our numerical investigation suggests that the evolution of the attracting domains in this dynamical system is very complicated, yet a worth studying problem. Highlights • The axisymmetric five body problem: the convex configuration has been studied. • The effect of angle parameters on the positions of libration points are discussed. • The Newton–Raphson iterative scheme is used to discuss the basins of convergence. [ABSTRACT FROM AUTHOR]

In this paper we numerically explore the convergence properties of the pseudo-Newtonian circular restricted problem of three and four primary bodies. The classical Newton–Raphson iterative scheme is used for revealing the basins of convergence and their respective fractal basin boundaries on the complex plane. A thorough and systematic analysis is conducted in an attempt to determine the influence of the transition parameter on the convergence properties of the system. Additionally, the roots (numerical attractors) of the system and the basin entropy of the convergence diagrams are monitored as a function of the transition parameter, thus allowing us to extract useful conclusions. The probability distributions, as well as the distributions of the required number of iterations are also correlated with the corresponding basins of convergence. [ABSTRACT FROM AUTHOR]

The Newton–Raphson basins of convergence, corresponding to the coplanar libration points (which act as attractors), are unveiled in the Copenhagen problem, where instead of the Newtonian potential and forces, a quasi-homogeneous potential created by two primaries is considered. The multivariate version of the Newton–Raphson iterative scheme is used to reveal the attracting domain associated with the libration points on various type of two-dimensional configuration planes. The correlations between the basins of convergence and the corresponding required number of iterations are also presented and discussed in detail. The present numerical analysis reveals that the evolution of the attracting domains in this dynamical system is very complicated, however, it is a worth studying issue. [ABSTRACT FROM AUTHOR]

The present manuscript deals with the restricted four-body problem when all the primaries are oblate spheroids. This paper unveils the effect of oblateness on the existence, locations and stability of the libration points. It is assumed that three oblate primaries having equal masses are set in Lagrangian equilateral triangle configuration. It is observed that there exist ten libration points in configuration ( x , y ) -plane out of which four are collinear and six are non-collinear for oblateness parameter A ∈ [ 0 , 0 . 681949 ) . Further, for the oblateness parameter A ∈ ( 0 . 681949 , 1 ) , there exist only four libration points out of which two are collinear and two are non-collinear. Out-of-plane libration points are also investigated and it is found that in-plane and out-of-plane libration points are unstable. It is further observed that oblateness parameter has substantial effect on the regions of possible motion. Further, we have numerically investigated the Newton–Raphson basins of convergence associated with the libration points to unveil that how the oblateness parameter influences the domain of convergence. [ABSTRACT FROM AUTHOR]