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Quasi-inverses and approximation with min-max operators in the ℓ1-norm
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: C.H. RohwerThe semi-group of min-max operators, as used for nonlinear smoothing or multiresolution analysis, has no nontrivial inverses. Having chosen a smoother for a specific purpose, the secondary approximation problem of minimising damage was considered by showing that quasi-inverses exist. This... -
A multimetric-index approach using fisheries data to assess fish assemblage structure in relation to salinity gradient in a tropical West African estuary
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: J Kantoussan --- Université Gaston Berger de Saint-Louis, Senegal JM Ecoutin --- Institut de Recherche pour le Développement (IRD), France R Laë --- Institut de Recherche pour le Développement (IRD), France OT Thiaw --- Institut Universitaire de Pêche et d’Aquaculture (IUPA), Université Cheikh Anta Diop de Dakar, Senegal L Tito de Morais --- Institut de Recherche pour le Développement (IRD), FranceThis study examines the effects of increasing salinity on fish assemblage structure in the Casamance Estuary, Senegal, using a series of indices. The study data were derived from commercial fishery surveys conducted between April and July 2005. Analysis of within-trophic-group... -
The W -weighted BT inverse
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: D.E. Ferreyra --- Universidad Nacional de Río Cuarto, Argentina N. Thome --- Instituto Universitario de Matemática Multidisciplinar, Universitat Politècnica de València, Spain C. Torigino --- Universidad Autónoma de Entre Ríos, ArgentinaIn this paper we extend the definition of BT inverse of square complex matrices to rectangular matrices. This new generalized inverse (called the W -weighted BT inverse) always exists and is unique. We investigate several characterizations of the W -weighted... -
On a functional identity involving inverses on matrix rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Nadeem Ahmad Dar --- Government HSS, India Wu Jing --- Fayetteville State University, USALet be a division ring which is not a field with characteristic different from 2 and 3, and with n > 1. The purpose of this paper is to characterize additive maps f,g : satisfying the functional identity f(X) +... -
Inverses and order boundedness of invertible ideal operators
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Kazım Özcan --- , Turkey Bahri Turan --- Gazi University, TurkeyIn this paper, we investigate that under which conditions the inverse of an invertible ideal operator becomes an ideal operator. To determine conditions, in the first case, we consider the center of a Riesz space and achieve the solution by... -
An inverse source problem for a nonlinear pseudoparabolic equation with p-Laplacian diffusion and damping term
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Khonatbek Khompysh --- Al-Farabi Kazakh National University, Kazakhstan Aidos Ganizhanuly Shakir --- Al-Farabi Kazakh National University, KazakhstanIn this work, we study the unique solvability of the inverse problem that consists of determining a weak solution u(x, t) to the nonlinear pseudoparabolic equation with p−Laplacian and damping term -
A generalization of the group inverse
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: D.E. Ferreyra --- Universidad Nacional de Río Cuarto, Argentina Saroj B. Malik --- Ambedkar University, IndiaFrom the point of view of generalizations, the core inverse of a matrix has received a lot of attention of researchers in this area resulting in many generalizations of the core inverse, like core-EP, DMP, BT, WC and so on... -
The order bidual of C(X) for a realcompact space
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Marcel de Jeu --- Mathematical Institute, Leiden University, the Netherlands Jan Harm van der Walt --- University of Pretoria, South AfricaIt is well known that the bidual of C(X) for a compact space X, supplied with the Arens product, is isometrically isomorphic as a Banach algebra to for some compact space . The space is unique up to homeomorphism. We... -
Scaling and instantaneous blow up
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Gisèle Ruiz Goldstein --- University of Memphis, USA Jerome A. Goldstein --- University of Memphis, USA İsmail Kömbe --- Istanbul Commerce University, Türkiye Abdelaziz Rhandi --- University of Salerno, ItalyThe main result is a simple proof of the Baras-Goldstein (1984) instantaneous blow up result for the heat equation with the inverse square potential. The proof relies heavily, indeed mainly, on scaling. Remarks are also given concerning the case when... -
Does participation in innovation platform improve welfare? Insights from smallholder maize farmers in Ghana
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Eric Asiamah Yeboah --- , Ghana Kelvin Balcombe --- University of Reading, UK Bright Owusu Asante --- Kwame Nkrumah University of Science and Technology (KNUST), Ghana Stephen Prah --- Kwame Nkrumah University of Science and Technology (KNUST), Ghana Robert Aidoo --- Kwame Nkrumah University of Science and Technology (KNUST), GhanaThis paper investigates the impact of participation in innovation platforms (IPs) on smallholder maize farmers’ welfare in the Brong Ahafo region of Ghana using data collected from 477 rural farm households. We employed the doubly robust inverse probability weighted regression... -
On EP matrices, partial isometry matrices and their numerical range
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Gholamreza Aghamollaei --- Shahid Bahonar University of Kerman, Iran Mahdiyeh Mortezaei --- Shahid Bahonar University of Kerman, Iran Mohammad Ali Nourollahi --- , IranIn this paper, some properties of the numerical range of some well-known generalized inverses of matrices, such as Moore-Penrose inverse, Drazin inverse, DMP inverse and CMP inverse, are investigated. In particular, an identification of EP matrices is given via the... -
Inverse problem of determining the coefficient in a sixth order Boussinesq equation with additional nonlocal integral condition
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: A.S. Farajov --- Azerbaijan State Pedagogical University, Azerbaijan M.J. Huntul --- Jazan University, Saudi Arabia Yashar T. Mehraliyev --- Baku State University, AzerbaijanThe work is devoted to the study of the solvability of the inverse boundary value problem with an unknown time depended coefficient for a sixth-order Boussinesq equation with an additional integral condition of the first kind is investigated. First, the... -
The proper homotopy of Alexandroff spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Tomás Fernández-Bayort --- Instituto Pablo Neruda, Spain Álvaro Luque --- Universidad de Sevilla, Spain Antonio Quintero --- Universidad de Sevilla, SpainThis paper introduces the study of the infinity in the class of Alexandroff spaces by establishing the proper category of locally finite Alexandroff spaces. We observe that the McCord and Clader theorems are available in this setting. The paper can... -
An inverse problem for pseudoparabolic equation: existence, uniqueness, stability, and numerical analysis
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Kh. Khompysh --- Al-Farabi Kazakh National University, Kazakhstan M.J. Huntul --- Jazan University, Saudi Arabia M.K. Shazyndayeva --- Al-Farabi Kazakh National University, Kazakhstan M.K. Iqbal --- Government College University, PakistanIn this paper, we study an inverse problem for a linear third-order pseudoparabolic equation. The investigated inverse problem consists of determining a space-dependent coefficient of the right-hand side of a pseudoparabolic equation. As an additional information a final overdetermination condition... -
A generalization of the MP-
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Water-quality assessment and spatial distribution of water-quality parameters of Dodoma Urban, Tanzania
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: OJ Mdee --- University of Dodoma, Tanzania B Mndolwa --- University of Dodoma, Tanzania N Sadiki --- University of Dodoma, TanzaniaThe study was conducted in 2022 in shallow wells and deep boreholes owned by residents, to investigate the water quality status in the emerging developing area of Dodoma Urban municipality in central Tanzania. Eighteen boreholes and five shallow wells were... -
The (B, C)-core inverse of rectangular matrices
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Huihui Zhu --- Hefei University of Technology, China Daihan Xu --- Hefei University of Technology, China Pedro Patrício --- Universidade do Minho, Portugal Dijana Mosić --- University of Niš, SerbiaLet A be an m × n complex matrix and let B, C be n × m complex matrices. The main purpose of this article is to derive several new properties of the (B, C)-core inverse. Also, we introduce and... -
On uniqueness theorems for the inverse q-Sturm–Liouville problems
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: F.A. Gawish --- Benha University, Egypt Z.S. Mansour --- Cairo University, EgyptWe establish two theorems that illustrate the uniqueness of inverse q-Sturm-Liouville problems based on a specified set of spectral data. The first uniqueness theorem employs the method of transformation operators to provide a q-analog of the Levinson-Marchenko uniqueness theorem. The... -
The Common Hermitian Solutions of the matrix equations
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Numerical solution of the simultaneous identification problem for a time-fractional diffusion equation
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Zhousheng Ruan --- East China University of Technology, P.R. China Jie Zhou --- East China University of Technology, P.R. China Guanghong Wan --- East China University of Technology, P.R. China Wen Zhang --- East China University of Technology, P.R. ChinaIt is a key problem to determine the initial diffusion time and initial value in a time fractional diffusion model when using the fractional diffusion model to describe the emerging anomalous diffusion phenomenons in real world. This paper considers a... -
Inverse Problem for Moore-Gibson-Thompson equation with integral overdetermination condition
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: A.A. Boltaev --- Bukhara State University, Uzbekistan D.K. Durdiev --- Institute of Mathematics at the Academy of Sciences of the Republic of Uzbekistan, Uzbekistan A.A. Rahmonov --- Institute of Mathematics at the Academy of Sciences of the Republic of Uzbekistan, UzbekistanThis article is dedicated to the solution of the initial-boundary value problem for the Moore-Gibson-Thompson equation and introduces the inverse problem of identifying the kernel using an additional integral condition. First, we prove the existence and uniqueness of the solution... -
One-sided W-core inverses of rectangular matrices
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Bing Dong --- School of Mathematics, Hefei University of Technology, China Daihan Xu --- School of Mathematics, Hefei University of Technology, China Huihui Zhu --- School of Mathematics, Hefei University of Technology, ChinaThe main purpose of this article is to introduce the w-core inverse (and its one-sided versions) of rectangular matrices. The relationship between the right W-core inverse and the left W-core inverse is studied. Several basic properties and characterizations on W-core... -
One-sided Drazin invertibility in Banach algebras and perturbations of B-Fredholm spectra
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Kai Yan --- Fuzhou University, P.R. ChinaThe famous Drazin inverse and generalized Drazin inverse were originally introduced by Drazin in 1958 and Koliha in 1996, respectively. In this paper, the author presents simplified notions of left and right (generalized) Drazin inverses, which are the one-sided versions...