Afrika Matematika最新文献

{"title":"A large family of third degree semiclassical forms of class three","authors":"Mohamed Khalfallah","doi":"10.1007/s13370-025-01294-w","DOIUrl":"10.1007/s13370-025-01294-w","url":null,"abstract":"<div><p>The aim of this contribution is to study several characterizations of a large family of symmetric semiclassical linear forms of class three which are of third degree. In fact, by using the Stieltjes function and the moments of those forms, we give necessary and sufficient conditions for a regular form to be at the same time of strict third degree (resp. second degree), symmetric and semiclassical of class three under conditions <span>(Phi (x)=x(x^4-1))</span> and <span>(Psi (0)in {0, 2})</span>. Thus, we focus our attention on the link between these forms and the Jacobi forms <span>(mathcal {V}_{q}^{k, l}:=mathcal {J}(k+q/3,l-q/3), k+lge -1, k, l in mathbb {Z}, qin {1,2})</span> (resp. <span>(mathcal {T}_{p,q}:=mathcal {J}(p-1/2,q-1/2), p+qge 0, p, q in mathbb {Z})</span>). All of them are rational transformations of the Jacobi form <span>(mathcal {V}:= mathcal {J} left( -2/3, -1/3 right) )</span> (resp. the Tchebychev form of first kind <span>(mathcal {T}:= mathcal {J} left( -1/2, -1/2 right) )</span>).</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curves of constant breadth in Galilean 4-space (mathbb {G}_4)","authors":"Adama Thiandoum","doi":"10.1007/s13370-025-01296-8","DOIUrl":"10.1007/s13370-025-01296-8","url":null,"abstract":"<div><p>In this paper, we study curves of constant breadth according to Serret-Frenet frame on 4-dimensional Galilean space <span>(mathbb {G}_4)</span> and characterize these curves in terms of torsion and curvature functions. We give an example of curves of constant breadth to illustrate main results.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Toeplitz-like operator with rational matrix symbol having poles on the unit circle: matrix representation and spectral analysis","authors":"Gilbert J. Groenewald,&nbsp;Sanne ter Horst,&nbsp;Jacob J. Jaftha,&nbsp;André C. M. Ran","doi":"10.1007/s13370-025-01291-z","DOIUrl":"10.1007/s13370-025-01291-z","url":null,"abstract":"<div><p>In this paper we consider a class of unbounded Toeplitz operators with rational matrix symbols that have poles on the unit circle and employ state space realization techniques from linear systems theory, as used in our earlier analysis in Groenewald et al. (J Math Anal Appl 532, Paper no. 127925, 2024) of this class of operators, to study the connection with semi-infinite Toeplitz matrices and to determine the essential spectrum and resolvent set.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01291-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"(Delta _h)-Appell versions of U-Bernoulli and U-Euler polynomials: properties, zero distribution patterns, and the monomiality principle","authors":"William Ramírez,&nbsp;Stiven Díaz,&nbsp;Alejandro Urieles,&nbsp;Clemente Cesarano,&nbsp;Shahid Ahmad Wani","doi":"10.1007/s13370-025-01286-w","DOIUrl":"10.1007/s13370-025-01286-w","url":null,"abstract":"<div><p>This paper explores the properties, generating functions, recurrence relations, and summation formulas of a novel class of polynomials, referred to as <span>(Delta _h)</span>-type <i>U</i>-Bernoulli and <span>(Delta _h)</span>-type <i>U</i>-Euler polynomials. We delve into the characterization of these polynomials, including the monomiality principle, and derive the corresponding derivative and multiplicative operators. Additionally, we provide computational values in tables and visually appealing representations of the zeros of these polynomials in figures, offering a comprehensive understanding of their behavior.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Splitting theorem of gradient (rho )-Einstein solitons","authors":"Absos Ali Shaikh,&nbsp;Prosenjit Mandal,&nbsp;Chandan Kumar Mondal","doi":"10.1007/s13370-025-01284-y","DOIUrl":"10.1007/s13370-025-01284-y","url":null,"abstract":"<div><p>In this paper, we have proved a weighted Laplacian comparison of distance function for manifolds with Bakry–Émery curvature bounded from below. Next, we have shown that a gradient <span>(rho )</span>-Einstein soliton with a bounded integral condition on Ricci curvature splits off a line isometrically. Moreover, using this result, we have established some boundedness conditions on scalar curvature of gradient <span>(rho )</span>-Einstein soliton.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01284-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast algorithms for non-convex tensor completion problems","authors":"Asia Kanwal,&nbsp;Mati ur Rahman,&nbsp;Salah Boulaaras","doi":"10.1007/s13370-025-01290-0","DOIUrl":"10.1007/s13370-025-01290-0","url":null,"abstract":"<div><p>Multi-dimensional image processing plays a pivotal role in diverse fields such as medicine, research, graphics, industry, remote sensing, virtual reality, and geospatial mapping, enabling advanced visualization and analysis. Traditional methods for processing multi-dimensional data, such as matrix-based singular value decomposition (SVD), often fail to capture the inherent multi-dimensional structure, leading to suboptimal performance in tasks like data recovery and feature extraction. To address these limitations, tensor singular value decomposition (t-SVD) has emerged as a powerful tool, specifically designed to handle the complex, multi-linear structures inherent in multi-dimensional data. Unlike matrix-based approaches, t-SVD operates directly on tensors, preserving the intrinsic relationships between dimensions and enabling more accurate representation and recovery of multi-dimensional data. Derived from t-SVD, surrogate functions such as the logDet function and Laplace function have been proposed to approximate the multi-rank of tensors, facilitating the recovery of the underlying structure of multi-dimensional images. However, real-world applications involving large-scale datasets (e.g., hyperspectral images, multispectral images, and grayscale videos) present significant computational challenges. Standard optimization algorithms, such as the alternating direction method of multipliers (ADMM), are often inefficient for solving the resulting large-scale non-convex optimization problems. To overcome these challenges, we propose efficient ADMM algorithms based on randomized singular value decomposition (r-SVD). These algorithms are specifically designed to handle the non-convexity and scalability issues associated with SVD-based optimization. We provide a detailed analysis of the computational complexity of the proposed algorithms, demonstrating their superiority over traditional methods in terms of efficiency and scalability. Extensive experiments on real-world datasets, including hyperspectral images, multispectral images, and grayscale videos, validate that our proposed algorithms achieve significant reductions in CPU time without compromising the quality of data recovery. By leveraging the strengths of r-SVD, our approach offers a robust and efficient solution for multi-dimensional image processing, addressing both theoretical and practical challenges in the field.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A generalization of ECS- modules via c-closed submodules","authors":"Enas Mustafa Kamil,&nbsp;Bijan Davvaz","doi":"10.1007/s13370-025-01285-x","DOIUrl":"10.1007/s13370-025-01285-x","url":null,"abstract":"<div><p>In this paper we present a new generalization of CS, ECS and CCLS- modules. If each “cec-closed submodule “in a module <i>M</i> is a “direct summand“, then <i>M</i> is referred to be CECS. It was demonstrated that every ECS and CCLS-module is generalized by the CECS property. We look at modules <i>M</i> that allow one to lift all homomorphism from a cec-closed submodule of <i>M</i> to <i>M</i>. Despite this, certain modules have some characteristics in common with CECS modules.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing a semigroup by its fuzzy interior antiideals and fuzzy m-interior antiideals","authors":"Madeleine Al Tahan,&nbsp;Sarka Hoskova-Mayerova","doi":"10.1007/s13370-025-01287-9","DOIUrl":"10.1007/s13370-025-01287-9","url":null,"abstract":"<div><p>Fuzzy sets serve as an extension of traditional sets, capable of handling imprecise information. On the other hand, semigroups represent a broader category than groups, finding utility across various interdisciplinary domains. Diverse subsets of semigroups have been investigated to enhance comprehension of their practical applications. Given the significance of both these ideas, exploring fuzzy subsets within semigroups carries substantial importance. In this paper, we characterize a semigroup through one of its (fuzzy) subsets; (fuzzy) interior antiideals. More precisely, we define interior antiideals and <i>m</i>-interior antiideals of a semigroup, illustrate them by examples, and study their properties. Furthermore, we extend this notion into a fuzzy context, examining the characteristics of fuzzy interior antiideals and fuzzy <i>m</i>-interior antiideals of a semigroup.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01287-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On LM-G-filter degree and its characterizations","authors":"Merin Jose,&nbsp;Sunil C. Mathew","doi":"10.1007/s13370-025-01281-1","DOIUrl":"10.1007/s13370-025-01281-1","url":null,"abstract":"<div><p>This paper introduces the concept of <i>LM</i>-G-filter degree of mappings from <span>(L^X rightarrow M)</span>. <i>LM</i>-G-filter degrees of mappings are characterized by <i>L</i>-pre G-filter spaces. Degrees to which an ordinary map is an <i>LM</i>-G-filter map, <i>LM</i>-G-filter preserving map and <i>LM</i>-G-filter isomorphism are also defined and their representations are obtained in several ways. Finally, the application potential of <i>LM</i>-G-filter degree in connection with various decision making situations is also brought out.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability analysis of some types of pseudo essential spectra under quasi compact perturbations","authors":"Naila Bouida,&nbsp;Hamadi Chaâben,&nbsp;Ines Walha","doi":"10.1007/s13370-025-01278-w","DOIUrl":"10.1007/s13370-025-01278-w","url":null,"abstract":"<div><p>The notion of pseudo essential spectra appears as one of famous generalization of the classical notion of essential spectra. In this paper, we analysis the stability result of perturbed pseudo upper (lower)-Fredholm, pseudo upper (lower)-Weyl and pseudo upper (lower)-Browder operators by means of quasi compact criterions of perturbation. We show some pseudo essential spectra relations between these kind of operators. In addition, a new characterization of the sum of two linear bounded operators in Banach spaces is invested in terms of some essential pseudo spectra based on sufficient criterion of quasi compact perturbation.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}