The classical SIRD model is extended to the conformable fractional stochastic SIRD model. The differences between the fractional stochastic SIRD model and the integer stochastic SIRD model are analyzed and compared using COVID-19 data from India. The results show that when the order of the fractional stochastic SIRD model is between $[0.93,0.99]$, the root mean square error between the simulated value and the real value of the number of infections is smaller than that of the integer stochastic SIRD model. Then, the maximum likelihood estimation of the parameters of the conformable fractional stochastic SIRD model is carried out, and compared with the maximum likelihood estimation results of the parameters of the integer stochastic SIRD model, It can be seen that the root mean square error of the fractional stochastic SIRD model is smaller when the fractional order is between $[0.93,0.99]$.
{"title":"Parameter Estimation for a Class of Fractional Stochastic SIRD Models with Random Perturbations","authors":"Na NİE, Jun JİANG, Yuqiang FENG","doi":"10.33401/fujma.1212268","DOIUrl":"https://doi.org/10.33401/fujma.1212268","url":null,"abstract":"The classical SIRD model is extended to the conformable fractional stochastic SIRD model. The differences between the fractional stochastic SIRD model and the integer stochastic SIRD model are analyzed and compared using COVID-19 data from India. The results show that when the order of the fractional stochastic SIRD model is between $[0.93,0.99]$, the root mean square error between the simulated value and the real value of the number of infections is smaller than that of the integer stochastic SIRD model. Then, the maximum likelihood estimation of the parameters of the conformable fractional stochastic SIRD model is carried out, and compared with the maximum likelihood estimation results of the parameters of the integer stochastic SIRD model, It can be seen that the root mean square error of the fractional stochastic SIRD model is smaller when the fractional order is between $[0.93,0.99]$.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136300829","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}
In this study, the system of nonlinear inequalities (SNI) problem is investigated. First, a new smoothing technique for the ``$max$'' function is proposed. Then, a new smoothing algorithm is developed in order to solve SNI by combining the smoothing technique with the iterative method. The new algorithm is applied to some numerical examples to show the efficiency of our algorithm.
{"title":"A New Smoothing Algorithm to Solve a System of Nonlinear Inequalities","authors":"Nurullah Yilmaz, Aysegul Kayacan","doi":"10.33401/fujma.1261409","DOIUrl":"https://doi.org/10.33401/fujma.1261409","url":null,"abstract":"In this study, the system of nonlinear inequalities (SNI) problem is investigated. First, a new smoothing technique for the ``$max$'' function is proposed. Then, a new smoothing algorithm is developed in order to solve SNI by combining the smoothing technique with the iterative method. The new algorithm is applied to some numerical examples to show the efficiency of our algorithm.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126189002","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}
The necessary requirements for half-lightlike and coisotropic lightlike submanifolds to be a Ricci soliton are obtained. Some examples of Ricci soliton half-lightlike and Ricci soliton coisotropic lightlike submanifolds are given. The Ricci soliton equation is investigated on totally geodesic, totally umbilical and irrotational lightlike submanifolds.
{"title":"Ricci Soliton Lightlike Submanifolds with co-dimenison 2","authors":"E. Kiliç, M. Gülbahar, Ecem Kavuk, Esra Erkan","doi":"10.33401/fujma.1277288","DOIUrl":"https://doi.org/10.33401/fujma.1277288","url":null,"abstract":"The necessary requirements for half-lightlike and coisotropic lightlike submanifolds to be a Ricci soliton are obtained. Some examples of Ricci soliton half-lightlike and Ricci soliton coisotropic lightlike submanifolds are given. The Ricci soliton equation is investigated on totally geodesic, totally umbilical and irrotational lightlike submanifolds.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"79 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115828231","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}
We investigate new upper bounds for the Berezin radius and Berezin norm of $2times2$ operator matrices using the Cauchy-Buzano inequality, and we propose a required condition for the equality case in the triangle inequalities for the Berezin norms. We also show various Berezin radius inequalities for matrices with $2times2$ operators.
{"title":"Berezin Radius Inequalities of Functonal Hilbert space operators","authors":"Hamdullah Basaran, M. Gürdal","doi":"10.33401/fujma.1254301","DOIUrl":"https://doi.org/10.33401/fujma.1254301","url":null,"abstract":"We investigate new upper bounds for the Berezin radius and Berezin norm of $2times2$ operator matrices using the Cauchy-Buzano inequality, and we propose a required condition for the equality case in the triangle inequalities for the Berezin norms. We also show various Berezin radius inequalities for matrices with $2times2$ operators.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133851185","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}
In this paper, we discuss some qualitative properties of the positive solutions to the following rational nonlinear difference equation ${x_{n+1}}=% frac{{alpha {x_{n-m}+eta {x_{n-k}{+sigma {x_{n-l}}}}+}}delta {{x_{n}}}}{% {beta +gamma {x_{n-k}}{x_{n-l}}left( {{x_{n-k}}+{x_{n-l}}}right) }}$, $% n=0,1,2,...$ where the parameters $alpha ,beta ,gamma ,delta ,{eta },{% sigma }in (0,infty )$, while $m,k,l$ are positive integers, such that $% m
{"title":"Qualitative Behavior of the difference equation ${x_{n+1}}=frac{{% alpha {x_{n-m}+eta {x_{n-k}{+sigma {x_{n-l}}}}+}}delta {{x_{n}}}}{{beta +gamma {x_{n-k}}{x_{n-l}}left( {{x_{n-k}}+{x_{n-l}}}right) }}$","authors":"Mohamed ABD EL-MONEAM","doi":"10.33401/fujma.1239100","DOIUrl":"https://doi.org/10.33401/fujma.1239100","url":null,"abstract":"In this paper, we discuss some qualitative properties of the positive \u0000solutions to the following rational nonlinear difference equation ${x_{n+1}}=% \u0000frac{{alpha {x_{n-m}+eta {x_{n-k}{+sigma {x_{n-l}}}}+}}delta {{x_{n}}}}{% \u0000{beta +gamma {x_{n-k}}{x_{n-l}}left( {{x_{n-k}}+{x_{n-l}}}right) }}$, $% \u0000n=0,1,2,...$ where the parameters $alpha ,beta ,gamma ,delta ,{eta },{% \u0000sigma }in (0,infty )$, while $m,k,l$ are positive integers, such that $% \u0000m","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131531103","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}
In this paper, we determine, in 3-dimensional homogenous Riemannian space $% mathbb{S}ol3$, the parametric flux surfaces according to Killing magnetic vectors and its associate scalar flux functions. An examples of shush surfaces are presented with a graphical representation in Euclidean space.
{"title":"Flux surfaces according to Killing magnetic vectors in Riemannian space $mathbb{S}ol3$","authors":"Nourelhouda Benmensour, F. Hathout","doi":"10.33401/fujma.1163741","DOIUrl":"https://doi.org/10.33401/fujma.1163741","url":null,"abstract":"In this paper, we determine, in 3-dimensional homogenous Riemannian space $% \u0000mathbb{S}ol3$, the parametric flux surfaces according to Killing magnetic \u0000vectors and its associate scalar flux functions. An examples of shush \u0000surfaces are presented with a graphical representation in Euclidean space.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123301125","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}
In this study, for the first time, a method is given for a developable ruled surface to be a constant angle ruled surface. The general equations of constant angle surfaces have been shown in the studies done so far. In this study, a new method is given on how to obtain a constant angled surface when any constant direction is given in Minkowski $3-$space.
{"title":"Constant Angle Ruled Surfaces in E_{1}^{3}","authors":"Aykut Has, B. Yilmaz, Y. Yaylı","doi":"10.33401/fujma.1218966","DOIUrl":"https://doi.org/10.33401/fujma.1218966","url":null,"abstract":"In this study, for the first time, a method is given for a developable ruled surface to be a constant angle ruled surface. The general equations of constant angle surfaces have been shown in the studies done so far. In this study, a new method is given on how to obtain a constant angled surface when any constant direction is given in Minkowski $3-$space.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114820351","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}
Time scale theory helps us to combine differential equations with difference equations. Especially in models such as biology, medicine and economics, since the independent variable is handled discrete, it requires us to analyze in discrete clusters. In these cases, the difference equations defined in Z are considered. Boundary value problems (BVP’s) are used to solve and model problems in many physical area. In this study, we examined spectral features of discrete Sturm-Liouville problem. We have given some examples to make subject understandable.
{"title":"ON SOME SPECTRAL PROPERTIES OF DISCRETE STURM-LIOUVILLE OPERATOR","authors":"Ayşe Çiğdem Yar, E. Yilmaz, Tuba Gulsen","doi":"10.33401/fujma.1242330","DOIUrl":"https://doi.org/10.33401/fujma.1242330","url":null,"abstract":"Time scale theory helps us to combine differential equations with \u0000difference equations. Especially in models such as biology, medicine and economics, \u0000since the independent variable is handled discrete, it requires us to \u0000analyze in discrete clusters. In these cases, the difference equations defined \u0000in Z are considered. Boundary value problems (BVP’s) are used to solve and \u0000model problems in many physical area. In this study, we examined spectral \u0000features of discrete Sturm-Liouville problem. We have given some examples \u0000to make subject understandable.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127237772","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}
In this study, firstly, each natural lift curve of the main curve is corresponded to the ruled surface by exploitting E. Study mapping and the relation among the subset of the tangent bundle of unit 2-sphere, Tbar{M} and ruled surfaces in IR^{3}. Secondly, the intersection of two ruled surfaces, which are obtained by using the relation given above, is examined for the condition of the zero-set of λ(u, v) = 0. Then, all redundant and non-redundant solutions of the zero-set are investigated. Furthermore, the degenerate situations (u, v) = 0, where the whole plane is degenerated by the zero-set,, are denoted. Finally, some examples are given to verify the results.
{"title":"An Examination for the Intersection of Two Ruled Surfaces","authors":"Emel Karaca","doi":"10.33401/fujma.1235668","DOIUrl":"https://doi.org/10.33401/fujma.1235668","url":null,"abstract":"In this study, firstly, each natural lift curve of the main curve is corresponded to the ruled surface by exploitting E. Study mapping and the relation among the subset of the tangent bundle of unit 2-sphere, Tbar{M} and ruled surfaces in IR^{3}. Secondly, the intersection of two ruled surfaces, which are obtained by using the relation given above, is examined for the condition of the zero-set of λ(u, v) = 0. Then, all redundant and non-redundant solutions of the zero-set are investigated. Furthermore, the degenerate situations (u, v) = 0, where the whole plane is degenerated by the zero-set,, are denoted. Finally, some examples are given to verify the results.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122600363","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}
In this article, pseudoparallel submanifolds for almost Kenmotsu (κ,μ,ν)-space are investigated. The almost Kenmotsu (κ,μ,ν)-space is considered on the concircular curvature tensor. Submanifolds of these manifolds with properties such as concircular pseudoparallel, concircular 2-pseudoparallel, concircular Ricci generalized pseudoparallel, and concircular 2-Ricci generalized pseudoparallel has been characterized. Necessary and sufficient conditions are given for the invariant submanifolds of almost Kenmotsu (κ,μ,ν)-space to be total geodesic according to the behavior of the κ,μ,ν functions.
{"title":"Some Important Properties of Almost Kenmotsu (κ,μ,ν)-Space on the Concircular Curvature Tensor","authors":"Tuğba Mert, M. Atc̣eken","doi":"10.33401/fujma.1191851","DOIUrl":"https://doi.org/10.33401/fujma.1191851","url":null,"abstract":"In this article, pseudoparallel submanifolds for almost Kenmotsu (κ,μ,ν)-space are investigated. The almost Kenmotsu (κ,μ,ν)-space is considered on the concircular curvature tensor. Submanifolds of these manifolds with properties such as concircular pseudoparallel, concircular 2-pseudoparallel, concircular Ricci generalized pseudoparallel, and concircular 2-Ricci generalized pseudoparallel has been characterized. Necessary and sufficient conditions are given for the invariant submanifolds of almost Kenmotsu (κ,μ,ν)-space to be total geodesic according to the behavior of the κ,μ,ν functions.","PeriodicalId":199091,"journal":{"name":"Fundamental Journal of Mathematics and Applications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127974152","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}
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