[EN] In this work, we performed an study about the domain of existence and uniqueness for an efficient fifth order iterative method for solving nonlinear problems treated in their infinite dimensional form. The hypotheses for the operator and starting guess are weaker than in the previous studies. We assume omega continuity condition on second order Frechet derivative. This fact it is motivated by showing different problems where the nonlinear operators that define the equation do not verify Lipschitz and Holder condition; however, these operators verify the omega condition established. Then, the semilocal convergence balls are obtained and the R-order of convergence and error bounds can be obtained by following thee main theorem. Finally, we perform a numerical experience by solving a nonlinear Hammerstein integral equations in order to show the applicability of the theoretical results by obtaining the existence and uniqueness balls.This research was partially supported by Ministerio de Economia y Competitividad under grant PGC2018-095896-B-C22.Singh, S.; Martínez Molada, E.; Kumar, A.; Gupta, DK. (2020). Domain of Existence and Uniqueness for Nonlinear Hammerstein Integral Equations. Mathematics. 8(3):1-11. https://doi.org/10.3390/math8030384S11183Hernández, M. A. (2001). Chebyshev’s approximation algorithms and applications. Computers & Mathematics with Applications, 41(3-4), 433-445. doi:10.1016/s0898-1221(00)00286-8Amat, S., Hernández, M. A., & Romero, N. (2008). A modified Chebyshev’s iterative method with at least sixth order of convergence. Applied Mathematics and Computation, 206(1), 164-174. doi:10.1016/j.amc.2008.08.050Argyros, I. K., Ezquerro, J. A., Gutiérrez, J. M., Hernández, M. A., & Hilout, S. (2011). On the semilocal convergence of efficient Chebyshev–Secant-type methods. Journal of Computational and Applied Mathematics, 235(10), 3195-3206. doi:10.1016/j.cam.2011.01.005Hueso, J. L., & Martínez, E. (2013). Semilocal convergence of a family of iterative methods in Banach spaces. Numerical Algorithms, 67(2), 365-384. doi:10.1007/s11075-013-9795-7Zhao, Y., & Wu, Q. (2008). Newton–Kantorovich theorem for a family of modified Halley’s method under Hölder continuity conditions in Banach space. Applied Mathematics and Computation, 202(1), 243-251. doi:10.1016/j.amc.2008.02.004Parida, P. K., & Gupta, D. K. (2007). Recurrence relations for a Newton-like method in Banach spaces. Journal of Computational and Applied Mathematics, 206(2), 873-887. doi:10.1016/j.cam.2006.08.027Parida, P. K., & Gupta, D. K. (2008). Recurrence relations for semilocal convergence of a Newton-like method in Banach spaces. Journal of Mathematical Analysis and Applications, 345(1), 350-361. doi:10.1016/j.jmaa.2008.03.064Cordero, A., Ezquerro, J. A., Hernández-Verón, M. A., & Torregrosa, J. R. (2015). On the local convergence of a fifth-order iterative method in Banach spaces. Applied Mathematics and Computation, 251, 396-403. doi:10.1016/j.amc.2014.11.084Argyros, I. K., & Hilout, S. (2013). On the local convergence of fast two-step Newton-like methods for solving nonlinear equations. Journal of Computational and Applied Mathematics, 245, 1-9. doi:10.1016/j.cam.2012.12.002Argyros, I. K., George, S., & Magreñán, Á. A. (2015). Local convergence for multi-point-parametric Chebyshev–Halley-type methods of high convergence order. Journal of Computational and Applied Mathematics, 282, 215-224. doi:10.1016/j.cam.2014.12.023Wang, X., Kou, J., & Gu, C. (2012). Semilocal Convergence of a Class of Modified Super-Halley Methods in Banach Spaces. Journal of Optimization Theory and Applications, 153(3), 779-793. doi:10.1007/s10957-012-9985-9Argyros, I. K., & Magreñán, Á. A. (2015). A study on the local convergence and the dynamics of Chebyshev–Halley–type methods free from second derivative. Numerical Algorithms, 71(1), 1-23. doi:10.1007/s11075-015-9981-xWu, Q., & Zhao, Y. (2007). Newton–Kantorovich type convergence theorem for a family of new deformed Chebyshev method. Applied Mathematics and Computation, 192(2), 405-412. doi:10.1016/j.amc.2007.03.018Martínez, E., Singh, S., Hueso, J. L., & Gupta, D. K. (2016). Enlarging the convergence domain in local convergence studies for iterative methods in Banach spaces. Applied Mathematics and Computation, 281, 252-265. doi:10.1016/j.amc.2016.01.036Kumar, A., Gupta, D. K., Martínez, E., & Singh, S. (2018). Semilocal convergence of a Secant-type method under weak Lipschitz conditions in Banach spaces. Journal of Computational and Applied Mathematics, 330, 732-741. doi:10.1016/j.cam.2017.02.042Singh, S., Gupta, D. K., Martínez, E., & Hueso, J. L. (2016). Semilocal Convergence Analysis of an Iteration of Order Five Using Recurrence Relations in Banach Spaces. Mediterranean Journal of Mathematics, 13(6), 4219-4235. doi:10.1007/s00009-016-0741-
