Pub Date : 2019-01-01DOI: 10.1080/25742558.2019.1602017
Rifaqat Ali, Wan Ainun Mior Othman
Abstract In the present article, we derive an inequality in terms of slant immersions and well define warping function for the squared norm of second fundamental form for warped product semi-slant submanifold in a locally product Riemannian manifold. Moreover, the equality cases are verified and generalized the inequality for semi-invariant warped products in locally Riemannain product manifold.
{"title":"Geometric inequality of warped product semi-slant submanifolds of locally product Riemannian manifolds","authors":"Rifaqat Ali, Wan Ainun Mior Othman","doi":"10.1080/25742558.2019.1602017","DOIUrl":"https://doi.org/10.1080/25742558.2019.1602017","url":null,"abstract":"Abstract In the present article, we derive an inequality in terms of slant immersions and well define warping function for the squared norm of second fundamental form for warped product semi-slant submanifold in a locally product Riemannian manifold. Moreover, the equality cases are verified and generalized the inequality for semi-invariant warped products in locally Riemannain product manifold.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1602017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41332917","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}
Pub Date : 2019-01-01DOI: 10.1080/25742558.2018.1564169
V. Aghapouramin, M. Nikmehr
Abstract Let α be an endomorphism of an arbitrary ring with identity. The aim of this article is to introduce the ideal of as an α-skew M-McCoy which is a generalization of α-rigid ideals and McCoy ideals and to investigate its properties. α-skew M-McCoy is an α-skew McCoy ideals relative to a monoid . The findings show that if for some positive integer and be an α-skew M-McCoy left ideal of then is α-skew M-McCoy left ideal of . Also if be a locally finite ring and be an α-skew M-McCoy left ideal of , then is α-semicommutative left ideal of .
{"title":"On α-skew McCoy ideals related to a monoid","authors":"V. Aghapouramin, M. Nikmehr","doi":"10.1080/25742558.2018.1564169","DOIUrl":"https://doi.org/10.1080/25742558.2018.1564169","url":null,"abstract":"Abstract Let α be an endomorphism of an arbitrary ring with identity. The aim of this article is to introduce the ideal of as an α-skew M-McCoy which is a generalization of α-rigid ideals and McCoy ideals and to investigate its properties. α-skew M-McCoy is an α-skew McCoy ideals relative to a monoid . The findings show that if for some positive integer and be an α-skew M-McCoy left ideal of then is α-skew M-McCoy left ideal of . Also if be a locally finite ring and be an α-skew M-McCoy left ideal of , then is α-semicommutative left ideal of .","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2018.1564169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48033325","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}
Pub Date : 2019-01-01DOI: 10.1080/25742558.2019.1703298
{"title":"Statement of Retraction: Design of an efficient and complete elicitation decision process in contingent valuation method","authors":"","doi":"10.1080/25742558.2019.1703298","DOIUrl":"https://doi.org/10.1080/25742558.2019.1703298","url":null,"abstract":"","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1703298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49452454","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}
Pub Date : 2019-01-01DOI: 10.1080/25742558.2019.1628513
William D. Fries, Miaohua Jiang
Abstract For a sequence of adjacency matrices, describing the unfolding of a network from the graph of a star, through graphs of a broom, to the graph of a link with constant vertices and edges, we show that the leading eigenvalue (the spectral radius) satisfies a simple algebraic equation. The equation allows easy numerical computation of the leading eigenvalue as well as a direct proof of its monotonicity in terms of the maximal degree of vertices.
{"title":"Leading eigenvalues of adjacency matrices of star-like graphs with fixed numbers of vertices and edges","authors":"William D. Fries, Miaohua Jiang","doi":"10.1080/25742558.2019.1628513","DOIUrl":"https://doi.org/10.1080/25742558.2019.1628513","url":null,"abstract":"Abstract For a sequence of adjacency matrices, describing the unfolding of a network from the graph of a star, through graphs of a broom, to the graph of a link with constant vertices and edges, we show that the leading eigenvalue (the spectral radius) satisfies a simple algebraic equation. The equation allows easy numerical computation of the leading eigenvalue as well as a direct proof of its monotonicity in terms of the maximal degree of vertices.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1628513","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42619631","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}
Pub Date : 2019-01-01DOI: 10.1080/25742558.2019.1602928
M. Dieye, M. Diop, K. Ezzinbi
Abstract In this work, we study the asymptotic behavior of the mild solutions of a class of stochastic partial functional integrodifferential equation on Hilbert spaces. Using the stochastic convolution developed, we establish the exponential stability in mean square with p ≥ 2. Also, pathwise exponential stability is proved for p> 2. We extend the result of an example is provided for illustration.
{"title":"Almost sure asymptotic stability for some stochastic partial functional integrodifferential equations on Hilbert spaces","authors":"M. Dieye, M. Diop, K. Ezzinbi","doi":"10.1080/25742558.2019.1602928","DOIUrl":"https://doi.org/10.1080/25742558.2019.1602928","url":null,"abstract":"Abstract In this work, we study the asymptotic behavior of the mild solutions of a class of stochastic partial functional integrodifferential equation on Hilbert spaces. Using the stochastic convolution developed, we establish the exponential stability in mean square with p ≥ 2. Also, pathwise exponential stability is proved for p> 2. We extend the result of an example is provided for illustration.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1602928","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48089349","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}
Pub Date : 2019-01-01DOI: 10.1080/25742558.2019.1624244
M. R. Alemi, F. Saeedi
Abstract Let and be two finite dimensional Lie algebras on arbitrary field F with no common direct factor and . In this article, we express the structure and dimension of derivation algebra of , , and some of their subalgebras in terms of , , , and .
{"title":"Derivation algebra of direct sum of lie algebras","authors":"M. R. Alemi, F. Saeedi","doi":"10.1080/25742558.2019.1624244","DOIUrl":"https://doi.org/10.1080/25742558.2019.1624244","url":null,"abstract":"Abstract Let and be two finite dimensional Lie algebras on arbitrary field F with no common direct factor and . In this article, we express the structure and dimension of derivation algebra of , , and some of their subalgebras in terms of , , , and .","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1624244","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44288950","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}
Pub Date : 2018-05-16DOI: 10.1080/25742558.2019.1683131
Naoya Yamaguchi
Abstract In this paper, we define the concept of the Study-type determinant, and we present some properties of these determinants. These properties lead to some properties of the Study determinant. The properties of the Study-type determinants are obtained using a commutative diagram. This diagram leads not only to these properties but also to an inequality for the degrees of representations and to an extension of Dedekind’s theorem.
{"title":"Study-type determinants and their properties","authors":"Naoya Yamaguchi","doi":"10.1080/25742558.2019.1683131","DOIUrl":"https://doi.org/10.1080/25742558.2019.1683131","url":null,"abstract":"Abstract In this paper, we define the concept of the Study-type determinant, and we present some properties of these determinants. These properties lead to some properties of the Study determinant. The properties of the Study-type determinants are obtained using a commutative diagram. This diagram leads not only to these properties but also to an inequality for the degrees of representations and to an extension of Dedekind’s theorem.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2019.1683131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42187187","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}
Pub Date : 2018-01-01DOI: 10.1080/25742558.2018.1475590
E. Omondi, Rachel Waema Mbogo, L. Luboobi
Abstract The control of spread of HIV to reduce its effects on a population is an important role of public health. HIV testing and counselling (HTC) and eventual enrolment of infected individuals on anti retro-viral treatment (ART) as soon as possible to reduce the risk of dying is currently the main intervention against HIV. Mathematical models can be used to study the effects of HIV prevention, testing and treatment with ART on HIV patients. In this study, we employ a deterministic model to provide a quantification of HIV prevention, testing and treatment with ART as public health measurements in the fight against HIV infection. Lyapunov function has been used to derive a condition that ensures that the model system is globally asymptotically stable when R0 is less than unity. Through sensitivity analysis, we determine the relative importance of model parameters for disease transmission. The sensitivity analysis results suggest that the effective contact rates are mechanisms fuelling HIV epidemic proliferation while ART efficacy reduces the incidence. The model is fitted to HIV surveillance data obtained from world in data website. Although the results show a high proportion of individuals with HIV in Kenya, the incidence curve is indicative of a declining HIV infection and settling at an endemic steady state. The results are suggestive of the need to promote preventive mechanism against the occurrence of new infections. Moreover, the results show that the combination of several control mechanisms would significantly reduce the spread of the disease, if we maintain the level of each control high.
{"title":"Mathematical modelling of the impact of testing, treatment and control of HIV transmission in Kenya","authors":"E. Omondi, Rachel Waema Mbogo, L. Luboobi","doi":"10.1080/25742558.2018.1475590","DOIUrl":"https://doi.org/10.1080/25742558.2018.1475590","url":null,"abstract":"Abstract The control of spread of HIV to reduce its effects on a population is an important role of public health. HIV testing and counselling (HTC) and eventual enrolment of infected individuals on anti retro-viral treatment (ART) as soon as possible to reduce the risk of dying is currently the main intervention against HIV. Mathematical models can be used to study the effects of HIV prevention, testing and treatment with ART on HIV patients. In this study, we employ a deterministic model to provide a quantification of HIV prevention, testing and treatment with ART as public health measurements in the fight against HIV infection. Lyapunov function has been used to derive a condition that ensures that the model system is globally asymptotically stable when R0 is less than unity. Through sensitivity analysis, we determine the relative importance of model parameters for disease transmission. The sensitivity analysis results suggest that the effective contact rates are mechanisms fuelling HIV epidemic proliferation while ART efficacy reduces the incidence. The model is fitted to HIV surveillance data obtained from world in data website. Although the results show a high proportion of individuals with HIV in Kenya, the incidence curve is indicative of a declining HIV infection and settling at an endemic steady state. The results are suggestive of the need to promote preventive mechanism against the occurrence of new infections. Moreover, the results show that the combination of several control mechanisms would significantly reduce the spread of the disease, if we maintain the level of each control high.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2018.1475590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45766623","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}
Pub Date : 2018-01-01DOI: 10.1080/25742558.2018.1556192
M. Natiello, Raúl H. Barriga, M. Otero, H. Solari
Abstract We develop a simulation method for Markov Jump processes with finite time steps based in a quasilinear approximation of the process and in multinomial random deviates. The second-order approximation to the generating function, Error = O(dt2), is developed in detail and an algorithm is presented. The algorithm is implemented for a Susceptible-Infected-Recovered-Susceptible (SIRS) epidemic model and compared to both the deterministic approximation and the exact simulation. Special attention is given to the problem of extinction of the infected population which is the most critical condition for the approximation.
{"title":"Multinomial approximation to the Kolmogorov Forward Equation for jump (population) processes","authors":"M. Natiello, Raúl H. Barriga, M. Otero, H. Solari","doi":"10.1080/25742558.2018.1556192","DOIUrl":"https://doi.org/10.1080/25742558.2018.1556192","url":null,"abstract":"Abstract We develop a simulation method for Markov Jump processes with finite time steps based in a quasilinear approximation of the process and in multinomial random deviates. The second-order approximation to the generating function, Error = O(dt2), is developed in detail and an algorithm is presented. The algorithm is implemented for a Susceptible-Infected-Recovered-Susceptible (SIRS) epidemic model and compared to both the deterministic approximation and the exact simulation. Special attention is given to the problem of extinction of the infected population which is the most critical condition for the approximation.","PeriodicalId":92618,"journal":{"name":"Cogent mathematics & statistics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/25742558.2018.1556192","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49024924","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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