https://www.revistaproyecciones.cl/index.php/proyecciones/issue/feed Proyecciones (Antofagasta, On line) 2024-06-17T00:00:00+00:00 Ricardo Soto Montero rsoto@ucn.cl Open Journal Systems <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> https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/5477 Pairwise Infra Neutrosophic Pre-Open Set in Infra Neutrosophic Bi-topological Space 2022-06-12T12:38:11+00:00 Suman Das sumandas18842@gmail.com Rakhal Das rakhaldas95@gmail.com <p>In this article, we present the notion of infra neutrosophic bi-topological spaces (in short INBTS) as a generalization of infra neutrosophic topological space (in short INTS) and neutrosophic bi-topological space (in short NBTS). Besides, we study the different types of open and closed sets namely infra neutrosophic bi-open set (in short INBOS), infra neutrosophic bi-semi-open set (in short INBSOS), infra neutrosophic bi-pre-open set (in short INBPOS), infra neutrosophic bi-<em>b</em>-open set (in short INB<em>b-</em>OS), etc. via INBTSs. Then, we introduce the notion of pairwise infra neutrosophic bi-open set (in short PINBOS), pairwise infra neutrosophic bi-semi-open set (in short PINBSOS), pairwise infra neutrosophic bi-pre-open set (in short PINBPOS), pairwise infra neutrosophic bi-<em>b</em>-open set (in short PINB<em>b</em>-OS), and furnish few illustrative examples on them. Further, we investigate several properties of these classes of sets and establish several interesting results via INBTSs in the form of propositions, theorems, etc.</p> 2024-06-17T00:00:00+00:00 Copyright (c) 2024 RAKHAL DAS, Suman Das https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6374 Fixed point and stability of nonlinear differential equations with variable delays 2024-02-13T14:13:43+00:00 Abdelhafid Younsi abehafidyounsi@gmail.com <p>In this paper, we study the stability of a generalized nonlinear differential equation with variable delays via fixed point theory. An asymptotic stability theorem with sufficient conditions is proved, which improves and generalizes some previous results. Two examples are given to illustrate our results.</p> 2024-06-17T00:00:00+00:00 Copyright (c) 2024 Abdelhafid younsi https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6286 Uniform stability, boundedness and square integrability for non-autonomous third-order neutral differential equations with delay 2024-02-11T05:03:40+00:00 Mebrouk Rahmane meb.rahmane@univ-adrar.edu.dz Fatima Abdellaoui abdellaouifatima11@gmail.com <p>The work in this article provides literature with some results concerning the exponential stability, the boundedness and the square integrability of solutions for some non autonomous equations of third order supplied with delay and neutral parameters. The main tool used in this work is the second method of Lyapunov. The article is finished by giving a concrete example that ensure the application of the obtained results.</p> 2024-06-17T00:00:00+00:00 Copyright (c) 2024 Mebrouk Rahmane, Fatima Abdellaoui https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6376 Singularity of cycle-spliced signed graphs 2024-04-11T11:54:43+00:00 Suliman Khan suliman.khan@unicampania.it Adriana Ciampella ciampell@unina.it <p>We consider the adjacency spectrum of cycle-spliced signed graphs (CSSG), i.e., signed graphs whose blocks are (independent) signed cycles. For a signed graph Σ, the nullity η(Σ) is the multiplicity of the 0-eigenvalue. The adjancency spectrum of cycle-spliced (signed) graphs is studied in the literature for the relation between the nullity η and the cyclomatic number c, in particular, it is known that 0≤η(Σ) ≤ c(Σ)+1. In this paper, nonsingular cycle-spliced bipartite signed graphs are characterized. For cycle-spliced signed graphs Σ having only odd cycles, we show that η(Σ) is 0 or 1. Finally, we compute the nullity of CSSGs consisting of at most three cycles.</p> 2024-06-17T00:00:00+00:00 Copyright (c) 2024 Adriana Ciampella, Suliman Khan https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6155 Stability and boundedness of solutions of certain Lienard-type non-autonomous differential equations 2024-05-04T18:05:29+00:00 Abdullai Abdurasid abdurasid.abdullai@yahoo.com A. L. Olutimo aolutimo@yahoo.com M. O. Omeike moomeike@yahoo.com <p>In this paper, the Liénard-type non-autonomous nonlinear differential equation</p> <p>ẍ+ p(t)f(x, ẋ) ẋ + q(t)g(x) = ϕ(t, x, ẋ)</p> <p>is investigated for uniform exponential asymptotic stability of solutions when ϕ(t, x, ẋ) ≡ 0, and uniform ultimate boundedness of solutions when ϕ(t, x, ẋ) ≠ 0, using the Lyapunov’s direct method</p> 2024-06-17T00:00:00+00:00 Copyright (c) 2024 Abdullai Abdurasid, Olutimo A.L., M. O. Omeike https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/5962 Coloring of Non-Zero Component Graphs 2023-07-03T16:19:58+00:00 Vrinda Mary Mathew vrinda.mathew@res.christuniversity.in Sudev Naduvath sudevmath@gmail.com <p>The non-zero component graph of finite dimensional vector space <strong>V</strong> over a finite field <strong>F</strong> is the graph G(V<sub>α</sub>)= (V,E), where vertices of G(V<sub>α</sub>) are the non-zero vectors in <strong>V</strong>, two of which are adjacent if they share at least one basis vector with non-zero coefficient in their basic representation. In this paper, we study the various types of colorings of non-zero component graph.</p> 2024-06-19T00:00:00+00:00 Copyright (c) 2024 Vrinda, Sudev Naduvath https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6158 A note on P-Sasakian manifolds satisfying certain conditions 2024-02-29T02:31:56+00:00 Pakize Uygun pakizeuygun@hotmail.com Mehmet Atçeken mehmet.atceken382@gmail.com <p>In the present paper, we have studied the curvature tensors of PSasakian manifold. For a P-Sasakian manifold, W<sub>1</sub> ·S = 0, W<sub>1</sub> ·Z = 0 and W<sub>9</sub> · W<sub>1</sub> = 0 cases are considered. According these cases, PSasakian manifolds have been characterized such as η-Einstein and Einstein. In addition, we research W<sub>1</sub>-flat and W<sub>9</sub>-flat for a PSasakian manifold. The results are interesting and give an idea about the geometry of P-Sasakian manifold.</p> 2024-06-19T00:00:00+00:00 Copyright (c) 2024 pakize uygun, Mehmet Atceken https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6174 A study on deg-centric graphs 2024-02-21T19:10:33+00:00 Timmy Tomy Thalavayalil timmy.thalavayalil@res.christuniversity.in Johan Kok johan.kok@christuniversity.in Sudev Naduvath sudevmath@gmail.com <p>The deg-centric graph of a simple, connected graph G, denoted by G<sub>d</sub>, is a graph constructed from G such that, V(G<sub>d</sub>) = V(G) and E(G<sub>d</sub>) = {v<sub>i</sub>v<sub>j</sub>: d<sub>G</sub>(v<sub>i</sub>,v<sub>j</sub>) ≤ deg<sub>G</sub>(v<sub>i</sub>)}. In this paper, the concepts of deg-centric graphs and iterated deg-centrication of a graph are introduced and discussed.</p> 2024-06-24T00:00:00+00:00 Copyright (c) 2024 Sudev Naduvath, Timmy, Johan https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/5828 Cayley fuzzy graphs on groups 2023-04-01T10:46:42+00:00 Mary John Jisha jjmakm@gmail.com A. Riyas riyasmaths@gmail.com K. Geetha geetha@tkmce.ac.in <p>We investigate some properties of Cayley fuzzy graphs on groups in terms of algebraic structures. And we also discuss the connectedness on it. In this paper, we prove that the Cayley fuzzy graph induced by (Z<sub>m</sub> × Z<sub>n</sub>, +, ν) is the disjoint union of Cay (aH, R) provided ν(h) &gt; 0 ∀ h ∈ H and ν(h′) =0 ∀ h′∈ Z<sub>m</sub> × Z<sub>n</sub>\H, where H is the cyclic subgroup of order n in Z<sub>m</sub> × Z<sub>n</sub>.</p> 2024-06-19T00:00:00+00:00 Copyright (c) 2024 JISHA MARY JOHN KAIMALIL HOUSE, A RIYAS, K GEETHA https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/5862 On the right automorphic generalised Bol loops 2023-01-25T06:55:45+00:00 Abdulafeez Olalekan Abdulkareem afeezokareem@gmail.com Y. T. Oyebo oyeboyt@yahoo.com J. O. Adeniran ekenedilichineke@yahoo.com <p>This study centers on right automophic generalised Bol loops. Having established the generators of inner mapping group of generalised Bol loops, some properties of generalised Bol loops, in terms of right translation map, are obtained. These properties are later used to established a condition under which right automorphic generalised Bol loop is a generalised Moufang loop.</p> 2024-06-24T00:00:00+00:00 Copyright (c) 2024 Dr. Abdulkareem A.O., Y.T Oyebo, J. O. Adeniran https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6179 Induced Dominating Sequence and ESD Graphs 2024-01-08T17:05:04+00:00 Liju Alex indulalgopal@gmail.com John Joy Mulloor indulalgopal@gmail.com Indulal Gopalapilla indulalgopal@gmail.com <p>A vertex subset D of a graph G = (V,E) is said to be a dominating set if every vertex in G is either in D or adjacent to some vertex in D. The minimum cardinality of such a set is the domination number, which is denoted as γ(G). In this paper, we define a sequence associated with the domination concept in graphs and studied the basic properties of the sequence in terms of various parameters of graphs. Using this sequence we order the vertices of a dominating set according its significance and propose Equally Significant Dominating (ESD) graphs. We also introduced domination related topological indices and compute their lower bounds for trees, unicyclic graphs and bicyclic graphs. All the graphs attaining the bounds are characterized.</p> 2024-06-19T00:00:00+00:00 Copyright (c) 2024 Indulal Gopalapilla, Liju Alex, John Joy https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/6412 A characterization of σ-prime rings involving generalized derivations 2024-04-01T13:32:19+00:00 Arshad Madni arshadmadni7613@gmail.com Muzibur Rahman Mozumder muzibamu81@gmail.com Wasim Ahmed wasim10041994@gmail.com Abu Zaid Ansari ansari.abuzaid@gmail.com <p>This paper’s major goal is to work on commutativity of σ-prime rings with second kind involution σ, involving generalized derivation satisfy the certain differential identities. Finally, we provide some examples to demonstrate that the conditions assumed in our results are not unnecessary</p> 2024-06-24T00:00:00+00:00 Copyright (c) 2024 Wasim Ahmed, Md. Arshad Madni, Muzibur Rahman Mozumder, Abu Zaid Ansari