Afrika Matematika最新文献

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Canal surfaces generated by special curves and quaternions 运河表面由特殊曲线和四元数生成
IF 1.1
Afrika Matematika Pub Date : 2023-11-17 DOI: 10.1007/s13370-023-01138-5
Abdussamet Çalışkan
{"title":"Canal surfaces generated by special curves and quaternions","authors":"Abdussamet Çalışkan","doi":"10.1007/s13370-023-01138-5","DOIUrl":"10.1007/s13370-023-01138-5","url":null,"abstract":"<div><p>In this paper, we show that canal and tubular surfaces can be obtained by special curves. Also, we give the equations of the canal and tubular surfaces given by the different frames. Besides, these surfaces are obtained by quaternion and homothetic motion.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138535","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}
引用次数: 0
Causal structure of spacetime and Scott topology 时空因果结构与斯科特拓扑学
IF 1.1
Afrika Matematika Pub Date : 2023-11-17 DOI: 10.1007/s13370-023-01122-z
Langelihle Mazibuko, Dharmanand Baboolal, Rituparno Goswami
{"title":"Causal structure of spacetime and Scott topology","authors":"Langelihle Mazibuko,&nbsp;Dharmanand Baboolal,&nbsp;Rituparno Goswami","doi":"10.1007/s13370-023-01122-z","DOIUrl":"10.1007/s13370-023-01122-z","url":null,"abstract":"<div><p>In this paper we establish the spacetime manifold as a partially ordered set via the casual structure. We show that these partially ordered sets are naturally continuous as a suitable way below relation can be established via the chronological order. We further consider those classes of spacetimes on which a lattice structure can be endowed by physically defining the joins and meets. By considering the physical properties of null geodesics on the spacetime manifold we show that these lattices are necessarily distributive. These lattices are then continuous as a result of the equivalence between the way below relation and chronology. This enables us to define the Scott topology on the spacetime manifold and describe it on an equal footing as any other continuous lattice. We further show that the Scott topology is a proper subset of Alexandroff topology, which must be the manifold topology for the strongly causal spacetimes, (and hence a coarser topology than Alexandroff). In the process we find some interesting results on the sobriety of these manifolds. We prove that they are necessarily not sober under the Scott topology but regain their sobriety under Alexandroff topology. We also define a dual Scott topology on these manifolds by endowing them with bicontinuous poset structure and show that the join of the Scott topology with the dual is the Alexandroff topology. We also discuss the previous works done in this topic and how the present work generalises those results to some extent.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-023-01122-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134878375","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}
引用次数: 0
Screen slant lightlike submanifolds of metallic semi-Riemannian manifolds 金属半黎曼流形的屏状斜光状子流形
IF 1.1
Afrika Matematika Pub Date : 2023-11-16 DOI: 10.1007/s13370-023-01123-y
Mehraj Ahmad Lone, Idrees Fayaz Harry
{"title":"Screen slant lightlike submanifolds of metallic semi-Riemannian manifolds","authors":"Mehraj Ahmad Lone,&nbsp;Idrees Fayaz Harry","doi":"10.1007/s13370-023-01123-y","DOIUrl":"10.1007/s13370-023-01123-y","url":null,"abstract":"<div><p>We introduce screen slant lightlike submanifolds of metallic semi-Riemannian manifolds. We find necessary and sufficient conditions for the induced connection to be a metric connection. Moreover, we investigate some equivalent conditions for integrability of such submanifolds.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796605","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}
引用次数: 0
Embedded varieties, X-ranks and uniqueness or finiteness of the solutions 嵌入变量、x阶和解的唯一性或有限性
IF 1.1
Afrika Matematika Pub Date : 2023-11-14 DOI: 10.1007/s13370-023-01133-w
E. Ballico
{"title":"Embedded varieties, X-ranks and uniqueness or finiteness of the solutions","authors":"E. Ballico","doi":"10.1007/s13370-023-01133-w","DOIUrl":"10.1007/s13370-023-01133-w","url":null,"abstract":"<div><p>Let <span>(Xsubset mathbb {P}^r)</span> be an integral and non-degenerate variety. For any <span>(qin mathbb {P}^r)</span> its <i>X</i>-rank <span>(r_X(q))</span> is the minimal cardinality of a finite subset of <i>X</i> whose linear span contains <i>q</i>. The solution set <span>(mathcal {S}(X,q))</span> of <span>(qin mathbb {P}^r)</span> is the set of all <span>(Ssubset X)</span> such that <span>(#S=r_X(q))</span> and <i>S</i> spans <i>q</i>. We prove that if <span>(Xne mathbb {P}^r)</span> there is at least one <i>q</i> with <span>(#mathcal {S}(X,q)&gt;1)</span> and that for almost all pairs (<i>X</i>, <i>q</i>) we have <span>(dim mathcal {S}(X,q)&gt;0)</span>.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796429","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}
引用次数: 0
A numerical algorithm for solitary wave solutions of the GEW equation GEW方程孤波解的数值算法
IF 1.1
Afrika Matematika Pub Date : 2023-11-13 DOI: 10.1007/s13370-023-01141-w
Melike Karta
{"title":"A numerical algorithm for solitary wave solutions of the GEW equation","authors":"Melike Karta","doi":"10.1007/s13370-023-01141-w","DOIUrl":"10.1007/s13370-023-01141-w","url":null,"abstract":"<div><p>The present article attempts to obtain numerical solutions for the GEW equation with the Lie–Trotter splitting algorithm. For this reason, in accordance with the rules of the algorithm, the main problem is split into two sub-equations, linear and non-linear. By applying Galerkin finite element method with cubic B-spline to each sub-equation, two numerical schemes are obtained and two problems for them are discussed. Error norms <span>(L_{2})</span> and <span>(L_{infty })</span> and three conservation properties <span>(I_{1},I_{2})</span> and <span>(I_{3})</span> are calculated to measure the reliability and performance of the proposed technique and find new approximate solutions. The results generated as a result of the calculation are compared with those produced by other methods in the literature. Stability analysis is examined using the Fourier method to indicate that the numerical approach is unconditionally stable. Based on the results obtained, it can be seen that this technique may be preferred to be applied to other partial differential equations such as the equation discussed in the current study.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796446","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}
引用次数: 0
Half-discrete of Hilbert inequality for three variables 三变量希尔伯特不等式的半离散
IF 1.1
Afrika Matematika Pub Date : 2023-11-13 DOI: 10.1007/s13370-023-01139-4
Nizar Kh. Al-Oushoush
{"title":"Half-discrete of Hilbert inequality for three variables","authors":"Nizar Kh. Al-Oushoush","doi":"10.1007/s13370-023-01139-4","DOIUrl":"10.1007/s13370-023-01139-4","url":null,"abstract":"<div><p>Through this research, we introduce two new forms of the half-discrete Hilbert inequality for three variables. In addition, we show that the constants that appear on the right-hand of inequalities are the best. Also, we introduce the equivalence forms of the two inequalities.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796447","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}
引用次数: 0
Classes of p-valent harmonic functions defined by q-derivative operator 由q导数算子定义的p价调和函数类
IF 1.1
Afrika Matematika Pub Date : 2023-11-13 DOI: 10.1007/s13370-023-01129-6
T. M. Seoudy
{"title":"Classes of p-valent harmonic functions defined by q-derivative operator","authors":"T. M. Seoudy","doi":"10.1007/s13370-023-01129-6","DOIUrl":"10.1007/s13370-023-01129-6","url":null,"abstract":"<div><p>In this paper we obtain coefficient characterization, extreme points and distortion bounds for the classes of <span>( p- )</span>valent harmonic functions defined by <span>(q-)</span>derivative operator. Some of our results improve and generalize previously known results.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796461","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}
引用次数: 0
Quasilinear elliptic systems with nonstandard growth conditions in Orlicz-Sobolev spaces Orlicz-Sobolev空间中具有非标准生长条件的拟线性椭圆系统
IF 1.1
Afrika Matematika Pub Date : 2023-11-12 DOI: 10.1007/s13370-023-01136-7
Farah Balaadich, Elhoussine Azroul
{"title":"Quasilinear elliptic systems with nonstandard growth conditions in Orlicz-Sobolev spaces","authors":"Farah Balaadich,&nbsp;Elhoussine Azroul","doi":"10.1007/s13370-023-01136-7","DOIUrl":"10.1007/s13370-023-01136-7","url":null,"abstract":"<div><p>An existence result for quasilinear elliptic systems with nonstandard growth/coercive conditions, <span>(W^{-1}L_{overline{M}})</span>-data and no sign condition is proved.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134878235","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}
引用次数: 0
Fixed point sets of multivalued rational contractions with stability analysis 具有稳定性分析的多值有理收缩不动点集
IF 1.1
Afrika Matematika Pub Date : 2023-11-11 DOI: 10.1007/s13370-023-01109-w
Binayak S. Choudhury, Nikhilesh Metiya, Sunirmal Kundu
{"title":"Fixed point sets of multivalued rational contractions with stability analysis","authors":"Binayak S. Choudhury,&nbsp;Nikhilesh Metiya,&nbsp;Sunirmal Kundu","doi":"10.1007/s13370-023-01109-w","DOIUrl":"10.1007/s13370-023-01109-w","url":null,"abstract":"<div><p>The present paper is on fixed point theory in set valued analysis. Here putting several concepts together, we define a set valued contraction and establish that such contractions have fixed points in a complete metric space. We have two main theorems in one of which we use <span>(alpha )</span>-regularity condition of the space as a substitute of the continuity requirement on the multivalued contraction. There are some illustrative examples and corollaries. We also perform stability analysis of fixed point sets. We establish that the fixed point sets associated with the mappings we consider in our theorems are stable. In the last section we discuss some consequences of the main results of this paper.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134795979","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}
引用次数: 0
A general stability result for swelling porous elastic media with nonlinear damping and nonlinear delay term 具有非线性阻尼和非线性延迟项的膨胀多孔弹性介质的一般稳定性结果
IF 1.1
Afrika Matematika Pub Date : 2023-11-11 DOI: 10.1007/s13370-023-01126-9
Abdelaziz Soufyane, Mounir Afilal, Tijani Apalara, Karim Rhofir
{"title":"A general stability result for swelling porous elastic media with nonlinear damping and nonlinear delay term","authors":"Abdelaziz Soufyane,&nbsp;Mounir Afilal,&nbsp;Tijani Apalara,&nbsp;Karim Rhofir","doi":"10.1007/s13370-023-01126-9","DOIUrl":"10.1007/s13370-023-01126-9","url":null,"abstract":"<div><p>We consider a swelling porous-elastic system with single nonlinear damping and nonlinear delay term in the elastic equation. We establish the general decay result using multiplier method.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"34 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134795980","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}
引用次数: 0
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