Demonstratio Mathematica最新文献

{"title":"Enhancing the accuracy and efficiency of two uniformly convergent numerical solvers for singularly perturbed parabolic convection–diffusion–reaction problems with two small parameters","authors":"K. Ansari, Mohammad Izadi, S. Noeiaghdam","doi":"10.1515/dema-2023-0144","DOIUrl":"https://doi.org/10.1515/dema-2023-0144","url":null,"abstract":"\u0000 <jats:p>This study is devoted to designing two hybrid computational algorithms to find approximate solutions for a class of singularly perturbed parabolic convection–diffusion–reaction problems with two small parameters. In our approaches, the time discretization is first performed by the well-known Rothe method and Taylor series procedures, which reduce the underlying model problem into a sequence of boundary value problems (BVPs). Hence, a matrix collocation technique based on novel shifted Delannoy functions (SDFs) is employed to solve each BVP at each time step. We show that our proposed hybrid approximate techniques are uniformly convergent in order <jats:inline-formula>\u0000 <jats:alternatives>\u0000 <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_dema-2023-0144_eq_001.png\" />\u0000 <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\u0000 <m:mi class=\"MJX-tex-caligraphic\" mathvariant=\"script\">O</m:mi>\u0000 <m:mrow>\u0000 <m:mo>(</m:mo>\u0000 <m:mrow>\u0000 <m:mi mathvariant=\"normal\">Δ</m:mi>\u0000 <m:msup>\u0000 <m:mrow>\u0000 <m:mi>τ</m:mi>\u0000 </m:mrow>\u0000 <m:mrow>\u0000 <m:mi>s</m:mi>\u0000 </m:mrow>\u0000 </m:msup>\u0000 <m:mo>+</m:mo>\u0000 <m:msup>\u0000 <m:mrow>\u0000 <m:mi>M</m:mi>\u0000 </m:mrow>\u0000 <m:mrow>\u0000 <m:mo>−</m:mo>\u0000 <m:mstyle displaystyle=\"false\">\u0000 <m:mfrac>\u0000 <m:mrow>\u0000 <m:mn>1</m:mn>\u0000 </m:mrow>\u0000 <m:mrow>\u0000 <m:mn>2</m:mn>\u0000 </m:mrow>\u0000 </m:mfrac>\u0000 </m:mstyle>\u0000 </m:mrow>\u0000 </m:msup>\u0000 </m:mrow>\u0000 <m:mo>)</m:mo>\u0000 </m:mrow>\u0000 </m:math>\u0000 <jats:tex-math>{mathcal{O}}left(Delta {tau }^{s}+{M}^{-tfrac{1}{2}})</jats:tex-math>\u0000 </jats:alternatives>\u0000 </jats:inline-formula> for <jats:inline-formula>\u0000 ","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140520135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Higher-order circular intuitionistic fuzzy time series forecasting methodology: Application of stock change index","authors":"Shahzaib Ashraf, Muhammad Sohail, Muhammad Shakir Chohan, Siriluk Paokanta, Choonkil Park","doi":"10.1515/dema-2023-0115","DOIUrl":"https://doi.org/10.1515/dema-2023-0115","url":null,"abstract":"Abstract This article presents a higher-order circular intuitionistic fuzzy time series forecasting method for predicting the stock change index, which is shown to be an improvement over traditional time series forecasting methods. The method is based on the principles of circular intuitionistic fuzzy set theory. It uses both positive and negative membership values and a circular radius to handle uncertainty and imprecision in the data. The circularity of the time series is also taken into consideration, leading to more accurate and robust forecasts. The higher-order forecasting capability of this method provides more comprehensive predictions compared to previous methods. One of the key challenges we face when using the amount featured as a case study in our article to project the future value of ratings is the influence of the stock market index. Through rigorous experiments and comparison with traditional time series forecasting methods, the results of the study demonstrate that the proposed higher-order circular intuitionistic fuzzy time series forecasting method is a superior approach for predicting the stock change index.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139454073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"L-Fuzzy fixed point results in ℱ -metric spaces with applications","authors":"Durdana Lateef","doi":"10.1515/dema-2022-0206","DOIUrl":"https://doi.org/10.1515/dema-2022-0206","url":null,"abstract":"Abstract Jleli and Samet in [On a new generalization of metric spaces, J. Fixed Point Theory Appl. 20 (2018), 128 (20 pages)] introduced the notion of ℱ -metric space as a generalization of traditional metric space and proved Banach contraction principle in the setting of this generalized metric space. The objective of this article is to use ℱ -metric space and establish some common fixed point theorems for ( β beta - ψ psi )-contractions. Our results expand, generalize, and consolidate several known results in the literature. As applications of the main result, the solution for fuzzy initial-value problems in the background of a generalized Hukuhara derivative was discussed.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139538066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On parameterized inequalities for fractional multiplicative integrals","authors":"Wen Sheng Zhu, B. Meftah, Hongyan Xu, Fahd Jarad, A. Lakhdari","doi":"10.1515/dema-2023-0155","DOIUrl":"https://doi.org/10.1515/dema-2023-0155","url":null,"abstract":"\u0000 In this article, we present a one-parameter fractional multiplicative integral identity and use it to derive a set of inequalities for multiplicatively \u0000 \u0000 \u0000 \u0000 s\u0000 \u0000 s\u0000 \u0000 -convex mappings. These inequalities include new discoveries and improvements upon some well-known results. Finally, we provide an illustrative example with graphical representations, along with some applications to special means of real numbers within the domain of multiplicative calculus.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140527022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral collocation method for convection-diffusion equation","authors":"Jin Li, Yongling Cheng","doi":"10.1515/dema-2023-0110","DOIUrl":"https://doi.org/10.1515/dema-2023-0110","url":null,"abstract":"\u0000 Spectral collocation method, named linear barycentric rational interpolation collocation method (LBRICM), for convection-diffusion (C-D) equation with constant coefficient is considered. We change the discrete linear equations into the matrix equation. Different from the classical methods to solve the C-D equation, we solve the C-D equation with the time variable and space variable obtained at the same time. Furthermore, the convergence rate of the C-D equation by LBRICM is proved. Numerical examples are presented to test our analysis.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140523600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the asymptotics of eigenvalues for a Sturm-Liouville problem with symmetric single-well potential","authors":"E. Başkaya","doi":"10.1515/dema-2023-0129","DOIUrl":"https://doi.org/10.1515/dema-2023-0129","url":null,"abstract":"\u0000 In this article, Sturm-Liouville problem with one boundary condition including an eigenparameter is considered, and the asymptotic expansion of its eigenparameter is calculated. The problem also has a symmetric single-well potential, which is an important function in quantum mechanics.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140517904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LADM procedure to find the analytical solutions of the nonlinear fractional dynamics of partial integro-differential equations","authors":"Qasim Khan, Hassan Khan, P. Kumam, Fairouz Tchier, Gurpreet Singh","doi":"10.1515/dema-2023-0101","DOIUrl":"https://doi.org/10.1515/dema-2023-0101","url":null,"abstract":"\u0000 Generally, fractional partial integro-differential equations (FPIDEs) play a vital role in modeling various complex phenomena. Because of the several applications of FPIDEs in applied sciences, mathematicians have taken a keen interest in developing and utilizing the various techniques for its solutions. In this context, the exact and analytical solutions are not very easy to investigate the solution of FPIDEs. In this article, a novel analytical approach that is known as the Laplace adomian decomposition method is implemented to calculate the solutions of FPIDEs. We obtain the approximate solution of the nonlinear FPIDEs. The results are discussed using graphs and tables. The graphs and tables have shown the greater accuracy of the suggested method compared to the extended cubic-B splice method. The accuracy of the suggested method is higher at all fractional orders of the derivatives. A sufficient degree of accuracy is achieved with fewer calculations with a simple procedure. The presented method requires no parametrization or discretization and, therefore, can be extended for the solutions of other nonlinear FPIDEs and their systems.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140519290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonparametric methods of statistical inference for double-censored data with applications","authors":"Asamh S. M. Al Luhayb","doi":"10.1515/dema-2023-0126","DOIUrl":"https://doi.org/10.1515/dema-2023-0126","url":null,"abstract":"\u0000 <jats:p>This article introduces new nonparametric statistical methods for prediction in case of data containing right-censored observations and left-censored observations simultaneously. The methods can be considered as new versions of Hill’s <jats:inline-formula>\u0000 <jats:alternatives>\u0000 <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_dema-2023-0126_eq_001.png\" />\u0000 <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\u0000 <m:msub>\u0000 <m:mrow>\u0000 <m:mi>A</m:mi>\u0000 </m:mrow>\u0000 <m:mrow>\u0000 <m:mrow>\u0000 <m:mo>(</m:mo>\u0000 <m:mrow>\u0000 <m:mi>n</m:mi>\u0000 </m:mrow>\u0000 <m:mo>)</m:mo>\u0000 </m:mrow>\u0000 </m:mrow>\u0000 </m:msub>\u0000 </m:math>\u0000 <jats:tex-math>{A}_{left(n)}</jats:tex-math>\u0000 </jats:alternatives>\u0000 </jats:inline-formula> assumption for double-censored data. Two bounds are derived to predict the survival function for one future observation <jats:inline-formula>\u0000 <jats:alternatives>\u0000 <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_dema-2023-0126_eq_002.png\" />\u0000 <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\">\u0000 <m:msub>\u0000 <m:mrow>\u0000 <m:mi>X</m:mi>\u0000 </m:mrow>\u0000 <m:mrow>\u0000 <m:mi>n</m:mi>\u0000 <m:mo>+</m:mo>\u0000 <m:mn>1</m:mn>\u0000 </m:mrow>\u0000 </m:msub>\u0000 </m:math>\u0000 <jats:tex-math>{X}_{n+1}</jats:tex-math>\u0000 </jats:alternatives>\u0000 </jats:inline-formula> based on each version, and these bounds are compared through two examples. Two interesting features are provided based on the proposed methods. The first one is the detailed graphical presentation of the effects of right and left censoring. The second feature is that the lower and upper survival functions can be derived.</jats:p>","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140523723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decay rate of the solutions to the Cauchy problem of the Lord Shulman thermoelastic Timoshenko model with distributed delay","authors":"A. Choucha, S. Boulaaras, Rashid Jan, M. Alnegga","doi":"10.1515/dema-2023-0143","DOIUrl":"https://doi.org/10.1515/dema-2023-0143","url":null,"abstract":"\u0000 In this study, we address a Cauchy problem within the context of the one-dimensional Timoshenko system, incorporating a distributed delay term. The heat conduction aspect is described by the Lord-Shulman theory. Our demonstration establishes that the dissipation resulting from the coupling of the Timoshenko system with Lord-Shulman’s heat conduction is sufficiently robust to stabilize the system, albeit with a gradual decay rate. To support our findings, we convert the system into a first-order form and, utilizing the energy method in Fourier space, and derive point wise estimates for the Fourier transform of the solution. These estimates, in turn, provide evidence for the slow decay of the solution.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140526851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The essential norm of bounded diagonal infinite matrices acting on Banach sequence spaces","authors":"Julio C. Ramos Fernández, María A. Rivera-Sarmiento, M. Salas-Brown","doi":"10.1515/dema-2023-0263","DOIUrl":"https://doi.org/10.1515/dema-2023-0263","url":null,"abstract":"\u0000 We calculate the essential norm of bounded diagonal infinite matrices acting on Köthe sequence spaces. As a consequence of our result, we obtain a recent criteria for the compactness of multiplication operator acting on Köthe sequence spaces.","PeriodicalId":10995,"journal":{"name":"Demonstratio Mathematica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140526126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}