In this paper we present an extension of fixed point theorem for self mappings on metric spaces endowed with a graph and which satisfies a Bianchini contraction condition. We establish conditions which ensure the existence of fixed point for a non-self Bianchini contractions T : K ⊂ X → X that satisfy Rothe’s boundary condition T (∂K) ⊂ K.

Several iterative processes have been defined by researchers to approximate the fixed points of various classes operators. In this paper we present, by using the basins of attraction for the roots of some complex polynomials, an empirical comparison of some iteration procedures for fixed points approximation of Newton's iteration operator. Some numerical results are presented. The Matlab m-file's for generating the basins of attraction are presented, too.

LetK be a non-empty closed subset of a Banach spaceX endowed with a graphG. The main result of this paper is a fixed point theorem for nonself KannanG-contractions T : K → X that satisfy Rothe’s boundary condition, i.e., T maps ∂K (the boundary of K) into K. Our new results are extensions of recent fixed point theorems for self mappings on metric spaces endowed with a partial order and also of various fixed point theorems for self and nonself mappings on Banach spaces or convex metric spaces. Acknowledgements. The second author’s research was done during his visit to Department of Mathematics and Statistics, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, in the period April-May 2016. He gratefully thanks Dr. AlHomidan, dean of College of Sciences, and Dr. Al-Attas, the Chairman of the Department of Mathematics and Statistics, for the excellent conditions they offered during the visit. The second author would like to acknowledge the support provided by the Deanship of Scientific Research at King Fahd University of Petroleum and Minerals for funding this work through the projects IN151014 and IN151017. The research was also supported by the CNCS-UEFISCDI project number PN-II-ID-PCE-2011-3-0087, ctr. No. 315.

We present an empirical study of the convergence area and speed of Agarwal et al. fixed point iterative procedure in the particular case of the Newton's method associated to the complex polynomials $p_{3}(z)=z^3-1$ and $p_{8}(z)=z^8-1$. In order to obtain an analytical expression for the experimental data related to the mean number of iterations (MNI) and convergence area index (CAI), we use regression analysis and find some linear and nonlinear bi-variable models with good correlation coefficients.

Let K be a non-empty closed subset of a Banach space X endowed with a graph G. The main result of this paper is a fixed point theorem for nonself Kannan G-contractions T : K → X that satisfy Rothe’s boundary condition, i.e., T maps ∂K (the boundary of K) into K. Our new results are extensions of recent fixed point theorems for self mappings on metric spaces endowed with a partial order and also of various fixed point theorems for self and nonself mappings on Banach spaces or convex metric spaces.

Let K be a non-empty closed subset of a Banach space X endowed with a graph G. We obtain fixed point theorems for nonself G-contractions of Chatterjea type. Our new results complement and extend recent related results [Berinde, V., Păcurar, M., The contraction principle for nonself mappings on Banach spaces endowed with a graph, J. Nonlinear Convex Anal. 16 (2015), no. 9, 1925-1936; Balog, L., Berinde, V., Fixed point theorems for nonself Kannan type contractions in Banach spaces endowed with a graph, Carpathian J. Math. 32 (2016), no. 3 (in press)] and thus provide more general and flexible tools for studying nonlinear functional equations.

In [YoonMe Ham et al., Some higher-order modifications of Newton’s method for solving nonlinear equations, J. Comput. Appl. Math., 222 (2008) 477–486], some higher-order modifications of Newton’s method for solving nonlinear equations are presented. In [Liang Fang et al., Some modifications of Newton’s method with higher-order convergence for solving nonlinear equations, J. Comput. Appl. Math., 228 (2009) 296–303], the authors point out some flaws in the results of YoonMe Ham et al. and present some modified variants of the method. In this paper we point out that the paper of Liang Fang et al. itself contains some flaw results and we correct them by using symbolic computation in Mathematica. Moreover, we show that the main result in Theorem 3 of Liang Fang et al. is wrong. The order of convergence of the method is’nt 3m+2, but is 2m+4. We give the general expression of convergence error too.

In this paper we study the sequences {xn}, {yn} defined for each n ≥ 1 by ... , in connection to Gamma and di-Gamma function. Our results generalize some previous ones in [Berinde, V. A new generalization of Euler’s constant, Creat. Math.Inform. 18 (2009), No. 2, 123–128] and [Sant ˆ am˘ arian, A., ˘ A generalization of Euler constant, Mediamira, Cluj-Napoca, 2008] and are inspired from the paper [Mortici, C., Improved convergence towards generalized Euler-Mascheroni constant, Appl. Math. Comput., 2009, doi: 10.1016/j.amc.2009.10.039].