Proyecciones (Antofagasta, On line) https://www.revistaproyecciones.cl/index.php/proyecciones <p align="justify">La revista&nbsp;Proyecciones. Journal of Mathematics es una publicación científica, sin fines de lucro, oficial de la Universidad Católica del Norte, Antofagasta, Chile. Fue fundada en 1982 y depende del Departamento de Matemáticas de la Universidad Católica del Norte.<br>Proyecciones. Journal of Mathematics edita un volumen con 5 números al año.</p> en-US rsoto@ucn.cl (Ricardo Soto Montero) revistas@ucn.cl (Revistas Científicas UCN) Wed, 03 Jun 2020 16:38:11 +0000 OJS 3.2.0.3 http://blogs.law.harvard.edu/tech/rss 60 Independent form of (?, s)-continuous functions in topological spaces https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4188 <p><em>We introduce a new class of almost contra-P<sub>?</sub>-continuous functions which is a subclass of the class of almost contra-precontinuous functions [8]. This class contains the classes of regular set connected functions, perfectly continuous functions and contra-P<sub>?</sub>-continuous functions. It is shown that almost contra-P<sub>?</sub>-continuity is independent to (?, s)-continuity [12] and contra-precontinuity [11]. Furthermore, we obtain basic properties and preservations theorems for almost contra-P<sub>?</sub>-continuity.</em></p> Brij K. Tyagi, Sumit Singh, Manoj Bhardwaj Copyright (c) 2020 Brij K. Tyagi, Sumit Singh, Manoj Bhardwaj http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4188 Wed, 03 Jun 2020 00:00:00 +0000 Total graph of a commutative semiring with respect to singular ideal https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3717 <p><em>Let S be a commutative semiring with unity. The singular ideal Z(S) of S is defined as Z(S) = {s ? S | sK = 0 for some essential ideal K of S}. In this paper, we introduce the notion of total graph of a commutative semiring with respect to the singular ideal. We define this graph as the undirected graph T(?(S)) with all elements of S as vertices and any two distinct vertices x and y are adjacent if and only if x + y ? Z(S). We discuss various characteristics of this total graph and also characterize some important properties of certain induced subgraphs of this total graph.</em></p> Nabanita Goswami, Helen K. Saikia Copyright (c) 2020 Nabanita Goswami, Helen K. Saikia http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3717 Wed, 03 Jun 2020 00:00:00 +0000 Existence of solution for some quasilinear parabolic systems with weight and weak monotonicity https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4201 <p><em>We prove the existence of weak solution u for the nonlinear parabolic systems:</em></p> <p><em>which is a Dirichlet Problem. In this system, v belongs to </em>, <em>f and g satisfy some standards continuity and growth conditions. We prove existence of a weak solution of different variants of this system under classical regularity for some</em> growth and coercivity for ? but with only very mild monotonicity assumptions.</p> Azroul Elhoussine, Barbara Abdelkrim, Rami El Houcine Copyright (c) 2020 Azroul Elhoussine, Barbara Abdelkrim, Rami El Houcine http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4201 Wed, 03 Jun 2020 00:00:00 +0000 Discussion on relation-theoretic for JS-quasi-contractions of uni/milti-dimensional mappings with transitivity https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3376 <p><em>We introduce the notion of a </em><em>JS<sub>R </sub>quasi</em><em>-contraction mapping, where R </em><em>is a binary relation on its domain. Also, we prove some fixed point results for such contractions in complete metric spaces endowed with a transitive relation. An example is given to substantiate our obtained theorems. In addition, we introduce a JS</em><em><sub>R</sub></em><em><sub>N</sub></em><em> -quasicontraction and also establish fixed point of N-order theorems for such contractions.</em></p> Kanokwan Sawangsup, Wutiphol Sintunavarat Copyright (c) 2020 Kanokwan Sawangsup, Wutiphol Sintunavarat http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3376 Wed, 03 Jun 2020 00:00:00 +0000 On a new difference sequence space https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3542 <p><em>In the present note, we define a new difference sequence </em><em>Dx </em><em>=(</em><em>Dx</em><em>)</em><em><sub>n</sub></em> <em>with the help of difference operator </em><em>D </em><em>as</em></p> <p><strong><em>&nbsp;</em></strong></p> <p>Also, we discuss some interesting properties of the proposed difference operator <em>D.</em></p> P. Baliarsingh, L. Nayak, P. Beuria Copyright (c) 2020 P. Baliarsingh, L. Nayak, P. Beuria http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3542 Wed, 03 Jun 2020 00:00:00 +0000 Maps preserving the square zero of ?-Lie product of operators https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3682 <p>Let B(H) be the algebra of all bounded linear operators on an infinite dimensional Hilbert space ?. In this paper, we identify the form of the unital surjective additive map ? : B(H)? B(H)which preserves the square zero of ?-Lie product of operators for some scalar ? with ? ? 0, 1, ?1.</p> Ali Taghavi, Roja Hosseinzadeh, Masoomeh Yousefi Copyright (c) 2020 Ali Taghavi, Roja Hosseinzadeh, Masoomeh Yousefi http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3682 Wed, 03 Jun 2020 00:00:00 +0000 Convergence analysis for combination of equilibrium problems and k-nonspreading set-valued mappings https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4211 <p>We find a common solution of generalized equilibrium problems and the set of fixed points of a k-nonspreading setvalued mapping by using shrinking projection hybrid method. Finally, we compare the shrinking solution set after randomization by giving numerical example which justifies our main result.</p> Suhel Ahmad Khan Khan, Kaleem Raza Kazmi, Watcharaporn Cholamjiak, Hemen Dutta Copyright (c) 2020 Suhel Ahmad Khan Khan, Kaleem Raza Kazmi, Watcharaporn Cholamjiak, Hemen Dutta http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/4211 Wed, 03 Jun 2020 00:00:00 +0000 Multi-item multi-objective fixed charged solid transportation problem with type-2 fuzzy variables https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3377 <p><em>A multi-item multi-objective fixed charged solid transportation problema with guidelines e.g. unit transportation penalty, amounts, requirements, and conveyances as type-2 triangular fuzzy variables with conditions on few items and conveyances is formulated here. A chance constrained programming model applying generalized credibility measure for the objective function as well as the constraints is formed with the critical value based reductions of corresponding type-2 fuzzy guidelines for this particular problem. The model is then converted into the equivalent crisp deterministic form. The optimal compromise solutions are obtained by fuzzy programming technique. An example is contributed to highlight the model and is then solved by applying Generalized Reduced Gradient (GRG) technique (applying LINGO 16). The sensitivity analysis of the model is also given to illustrate the model.</em></p> Dhiman Dutta, Mausumi Sen, Biplab Singha Copyright (c) 2020 Dhiman Dutta, Mausumi Sen, Biplab Singha http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3377 Wed, 03 Jun 2020 00:00:00 +0000 Sharp inequality of three point Gauss-Legendre quadrature rule https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3605 <p>An interesting identity for 3-point Gauss-Legendre quadrature rule using functions that are n-times differentiable. By applying the established identity, a sharp inequality which gives an error bound for 3-point Gauss-Legendre quadrature rule and some generalizations are derived. At the end, an application in numerical integration is given.</p> Artion Kashuri Copyright (c) 2020 Artion Kashuri http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3605 Thu, 28 May 2020 00:00:00 +0000 Effectiveness of Cannon and composite set of polynomials of two complex variables in Faber regions https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3599 <p>Conditions are obtained for effectiveness of Cannon and Composite sets of polynomials of two complex variables in Faber regions. It generalizes to these regions the results of Nassif on composite sets in balls of centre origin whose constituents are also cannon sets.</p> Jerome Ajayi Adepoju, Adesanmi Alao Mogbademu Copyright (c) 2020 Jerome Ajayi Adepoju, Adesanmi Alao Mogbademu http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3599 Wed, 03 Jun 2020 00:00:00 +0000 Erdelyi-Kober fractional Integrals on Hardy space and BMO https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3660 <p><em>The mapping properties of the multi. Erdélyi- Kober fractional integral operators on Hardy space and BMO. In particular, our main result gives the boundedness of the Erdélyi-Kober fractional integrals, the hypergeometric fractional integrals and the two-dimensional Weyl integrals on Hardy space and BMO.</em></p> Kwok-Pun Ho Copyright (c) 2020 Kwok-Pun Ho http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3660 Wed, 03 Jun 2020 00:00:00 +0000 Some bounds for relative autocommutativity degree https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3645 <pre>We consider the probability that a randomly chosen element of a subgroup of a finite group $G$ is fixed by an automorphism of $G$. We obtain several bounds for this probability and characterize some finite groups with respect to this probability. </pre> Rajat Kanti Nath, Parama Dutta Copyright (c) 2020 Rajat Kanti Nath, Parama Dutta http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3645 Wed, 03 Jun 2020 00:00:00 +0000 The P-Hausdorff, P-regular and P-normal ideal spaces https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3723 <p><em>We introduce and study new extensions of some separation axioms to ideal topological spaces, which we have called <strong>????</strong>-Hausdorff, <strong>????</strong>-regular and <strong>????</strong>-normal. These extensions are quite natural and represent a good improvement with respect to other extensions that have recently occurred, in which a level of separation that can be considered acceptable is not perceived.</em></p> <p> </p> Néstor Raúl Pachón Rubiano Copyright (c) 2020 Néstor Raúl Pachón Rubiano http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3723 Thu, 14 May 2020 00:00:00 +0000 A Chebyshev pseudo spectral method for solving fractional differential equations https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3680 <p><em><span class="fontstyle0">The Chebyshev pseudo-spectral method is generalized for solving fractional differential equations with initial conditions. For this purpose, an appropriate representation of the solution is presented and the Chebyshev pseudo-spectral differentiation matrix of fractional order is derived. Then, by using Chebyshev pseudo-spectral scheme, the problem is reduced to the solution of a system of algebraic equations.</span></em></p> AllahBakhsh Yazdani Cherati, Morteza Mohammadnezhad Kiasari Copyright (c) 2020 AllahBakhsh Yazdani Cherati, Morteza Mohammadnezhad Kiasari http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3680 Wed, 03 Jun 2020 00:00:00 +0000 The diophantine problem for addition and divisibility for subrings of rational functions over finite fields https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3666 <p><em>It is shown that the positive existential theory of the structure </em>?<sub>S</sub> = (S<sup>?1</sup>F[<em>t</em>];=,F, 0, 1,+, |,<em> f </em>? <em>tf), where f </em><em>?</em><em> tf is the multiplication by t map, S is non-empty a finite set of irreducible polynomials, and F is a finite field of odd characteristic, is undecidable</em>.</p> Leonidas Antonio Cerda-Romero, Carlos Martínez-Ranero Copyright (c) 2020 Leonidas Antonio Cerda-Romero, Carlos Martínez-Ranero http://creativecommons.org/licenses/by/4.0 https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/3666 Wed, 03 Jun 2020 00:00:00 +0000