http://revistas.ufro.cl/index.php/cubo/issue/feedCUBO, A Mathematical Journal2018-07-31T16:28:44-04:00Mauricio Godoy Molinacubo@ufrontera.clOpen Journal Systems<p align="justify">CUBO, A Mathematical Journal is a scientific journal founded in 1985, published by the Universidad de La Frontera, Temuco - Chile. The journal publishes original papers containing substantial results in areas of pure and applied mathematics. CUBO appears in three issues per year and is indexed in ZentralBlatt Math., Mathematical Reviews, MathSciNet and Latindex.</p>http://revistas.ufro.cl/index.php/cubo/article/view/1625 The Solvability and Fractional Optimal Control for Semilinear Stochastic Systems2018-06-27T02:34:34-04:00Surendra Kumarmathdma@gmail.com<p>This paper deals with fractional optimal control for a class of semilinear stochastic equation in Hilbert space setting. To ensure the existence and uniqueness of mild solution, a set of sufficient conditions is constructed. The existence of fractional optimal control for semilinear stochastic system is also discussed. Finally, an example is included to show the applications of the developed theory.</p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##http://revistas.ufro.cl/index.php/cubo/article/view/1626 Periodicity and stability in neutral nonlinear differential equations by Krasnoselskii’s fixed point theorem2018-07-17T16:47:38-04:00Bouzid Mansourimansouri.math@yahoo.frAbdelouaheb Ardjouniabd_ardjouni@yahoo.frAhcene Djoudiabd_ardjouni@yahoo.fr<p>The nonlinear neutral functional differential equation with variable delay is investigated. By using Krasnoselskii’s fixed point theorem we obtain the existence and the asymptotic stability of periodic solutions. Sufficient conditions are established for the existence and the stability of the above equation. Our results extend some results obtained in the work [19].</p> <p><img src="/public/site/images/mgodoy/Imagen1_vol19_n3_art21.jpg" alt="" width="792" height="56"></p> <p> </p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##http://revistas.ufro.cl/index.php/cubo/article/view/1627 On the solution set of a fractional integro-differential inclusion involving Caputo-Katugampola derivative2018-06-27T02:39:54-04:00Aurelian Cerneaacernea@fmi.unibuc.ro<p>We study an initial value problem associated to a fractional integro-differential inclusion defined by Caputo-Katugampola derivative and by a set-valued map with nonconvex values. We prove the arcwise connectedness of the solution set and that the set of selections corresponding to the solutions of the problem considered is a retract of the space of integrable functions on a given interval.</p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##http://revistas.ufro.cl/index.php/cubo/article/view/1628 Weak homoclinic solutions to discrete nonlinear problems of Kirchhoff type with variable exponents2018-06-27T02:38:54-04:00Aboudramane Guiroabouguiro@yahoo.frIdrissa Ibrangoibrango2006@yahoo.frStanislas Ouaroouaro@yahoo.fr<p>In this paper, we prove the existence of weak homoclinic solutions for discrete nonlinear problems of Kirchhoff type. The proof of the main result is based on a minimization method. As extension, we prove the existence result of weak homoclinic solutions for more general data depending on the solutions.</p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##http://revistas.ufro.cl/index.php/cubo/article/view/1630 Existence of solutions for discrete boundary value problems with second order dependence on parameters2018-06-27T02:39:31-04:00Aboudramane Guiroabouguiro@yahoo.frIdrissa Ibrangoibrango2006@yahoo.fr<p>We prove the existence of non trivial solution for discrete nonlinear problems of Kirchhoff type. The proof of the main result is based on a mountain pass lemma.</p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##http://revistas.ufro.cl/index.php/cubo/article/view/1872 Totally Degenerate Extended Kleinian Groups2018-07-31T16:28:44-04:00Rubén A. Hidalgoruben.hidalgo@ufrontera.cl<p>The theoretical existence of totally degenerate Kleinian groups is originally due to Bers and Maskit. In fact, Maskit proved that for any co-compact non-triangle Fuchsian group acting on the hyperbolic plane ℍ<sup>2</sup> there is a totally degenerate Kleinian group algebraically isomorphic to it. In this paper, by making a subtle modification to Maskit’s construction, we show that for any non-Euclidean crystallographic group F, such that ℍ<sup>2</sup>/F is not homeomorphic to a pant, there exists an extended Kleinian group G which is algebraically isomorphic to F and whose orientation-preserving half is a totally degenerate Kleinian group. Moreover, such an isomorphism is provided by conjugation by an orientation-preserving homeomorphism ϕ : ℍ<sup>2</sup> → Ω, where Ω is the region of discontinuity of G. In particular, this also provides another proof to Miyachi’s existence of totally degenerate finitely generated Kleinian groups whose limit set contains arcs of Euclidean circles.</p>2017-10-01T00:00:00-03:00##submission.copyrightStatement##