Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201On the rank of the holomorphic solutions of PDE associated to directed graphs19412110.22060/ajmc.2020.18413.1031ENHamidDamadiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranFarhadRahmatiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranJournal Article20200511Let G be a directed graph with m vertices and n edges, I(B) the<br />binomial ideal associated to the incidence matrix B of the graph G, and I_L the lattice<br />ideal associated to the columns of the matrix B. Also let B_i be a submatrix of<br />B after removing the ith column. In this paper it is determined that which prime<br />minimal ideals of I(B_i) are Andean or toral. Then we study the rank of the space<br />of solutions of binomial D-module associated to I(B_i) as A-graded ideal, where A is<br />a matrix that, AB_i = 0. Afterwards, we define a maximal cellular cycle and prove<br />that for computing this rank it is enough to consider these components of G. We<br />introduce some bounds for the number of the vertices of the convex hull generated<br />by the columns of the matrix A. Finally an algorthim is introduced by which we can<br />compute the volume of the convex hull corresponded to a cycles with k diagonals, so<br />by Theorem 2.1 the rank of (D / H_A(I(B_i); beta)) can be computed.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201Recognition by degree prime-power graph and order of some characteristically simple group1115412210.22060/ajmc.2020.18418.1033ENAfsaneBahriDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranBehroozKhosraviDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic)MortezaBaniasad AzadDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic)Journal Article20200512In this paper, by the order of a group and triviality of $O_p(G)$ for some prime $p$, we give a new characterization for some characteristically simple groups. In fact, we prove that if pϵ{5, 17, 23, 37, 47, 73} and n≤p, where $n$ is a natural number, then $Gcong{{rm PSL}(2,p)}^{n}$ if and only if $ |G|=|{{rm PSL}(2,p)}|^{n}$ and $ O_p(G)=1$.}<br /><br />Recently in [Qin, Yan, Shum and Chen, Comm. Algebra, 2019], the degree prime-power graph of a finite group <br /> have been introduced and it is proved that the Mathieu groups are uniquely determined by their degree prime-power graphs and orders. As a consequence of our results, we show that ${rm PSL}(2,p)^n$, where pϵ{5,17,23,37,47,73} and n≤p are uniquely determined by their degree prime-power graphs and orders.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201A class of operator related weighted composition operators between Zygmund space1725413210.22060/ajmc.2020.18833.1041ENEbrahimAbbasiDepartment of Mathematics&lrm;, &lrm;Mahabad Branch&lrm;, &lrm;Islamic Azad University&lrm;, &lrm;Mahabad&lrm;, &lrm;IranJournal Article20200806Let $mathbb {D}$ be the open unit disk in the complex plane $mathbb{C}$ and $H(mathbb{D})$ be the set of all analytic functions on $mathbb{D}$. Let $u, vin H(mathbb{D})$ and $varphi$ be an analytic self-map of $mathbb{D}$. A class of operator-related weighted composition operators<br />is defined as follow<br />begin{align*}<br />T_{u, v, varphi}f(z) = u(z) f{(varphi(z))}+ v(z) f'(varphi(z)) ,quad fin H(mathbb{D} ), quad zin mathbb{D}.<br />end{align*}<br /><br />In this work, we obtain some new characterizations for boundedness and essential norm of<br /> operator $T_{u, v, varphi}$ between Zygmund space.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201On GDW-Randers metrics on tangent Lie groups2736416010.22060/ajmc.2020.18572.1038ENMonaAtashafrouzDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranBehzadNajafiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranAkbarTayebiDepartment of Mathematics, Faculty of Science, University of Qom, Qom, IranJournal Article20200610Let $G$ be a Lie group equipped with a left-invariant Randers metric $F$. Suppose that $F^v$ and $F^c$ denote the vertical and complete lift of $F$ on $TG$, respectively. We give the necessary and sufficient conditions under which $F^v$ and $F^c$ are generalized Douglas-Weyl metrics. Then, we characterize all 2-step nilpotent Lie groups $G$ such that their tangent Lie groups $(TG, F^c)$ are generalized Douglas-Weyl Randers metrics.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201Conservation law and Lie symmetry analysis of foam drainage equation3744416110.22060/ajmc.2020.18460.1036ENMehdiNadjafikhahSchool of Mathematics, Iran University of Science and Technology0000-0002-1354-9786OmidChekiniSchool of Mathematics, Iran University of Science and TechnologyJournal Article20200518In this paper, using the Lie group analysis method, we study the group invariant of the Foam Drainage equation. It shows that this equation can be reduced to ODE. Also we apply the Lie-group classical, and the nonclassical method due to Bluman and Cole to deduce symmetries of the Foam Drainage equation. and we prove that the nonclassical method applied to the equation leads to new reductions, which cannot be obtained by Lie classical symmetries. Also this paper shows how to construct directly the local conservation laws for this equationAmirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201An extension of the Cardioid distributions on circle4552420910.22060/ajmc.2020.18285.1029ENErfanSalavatiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran0000-0001-8214-5518Journal Article20200418A new family of distributions on the circle is introduced which is a generalization of the Cardioid distributions. The elementary properties such as mean, variance, and the characteristic function are computed. The distribution is shown to be either unimodal or bimodal. The modes are computed. The symmetry of the distribution is characterized. The parameters are shown to be canonic (i.e. uniquely determined by the distribution). This implies that the estimation problem is well-defined. We also show that this new family is a subset of distributions whose Fourier series has degree at most 2 and study the implications of this property. Finally, we study the maximum likelihood estimation for this family.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201Estimation of the parameter of Levy distribution using ranked set sampling5360421610.22060/ajmc.2020.18499.1037ENSaharDornianiDepartment of Statistics, Roudehen
Branch, Islamic Azad University, Tehran, IranAdelMohammadpourDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranNaderNematollahiDepartment of Statistics, Allameh Tabataba'i
University, Tehran, Iran.Journal Article20200527Ranked set sampling is a statistical technique for data collection that generally<br />leads to more efficient estimators than competitors based on simple random sampling.<br />In this paper, we consider estimation of scale parameter of Levy distribution<br /> using a ranked set sample. We derive the best linear unbiased estimator<br />and its variance, based on a ranked set sample. Also we compare numerically, variance of this estimator with mean square error of the maximum likelihood, a median based estimator and an estimator based on Laplace transform. It turns out that the best linear unbiased estimator based on ranked set sampling is more efficient than other mentioned estimators.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201Some conformal vector fields and conformal Ricci solitons on N(k)-contact metric manifolds6171424610.22060/ajmc.2021.19220.1043ENUday ChandDeDepartment of Pure Mathematics, Faculty of Science, University of Calcutta, Kolkata, IndiaArpanSardarDepartment of Mathematics, Faculty of Science, University of Kalyani, West Bengal, IndiaAvijitSarkarDepartment of Mathematics, Faculty of Science, University of Kalyani, West BengalJournal Article20201105Abstract. The target of this paper is to study N(k)-contact metric manifolds<br />with some types of conformal vector fields like φ-holomorphic planar conformal<br />vector fields and Ricci biconformal vector fields. We also characterize N(k)-<br />contact metric manifolds allowing conformal Ricci almost soliton. Obtained results are supported by examples.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201On the reversible geodesics of a Finsler space endowed with a special deformed (α,β)-metric7380427010.22060/ajmc.2021.19522.1048ENLaurian-IoanPişcoranDepartment of Mathematics and Computer Science, Victoriei 76, 430122 Baia Mare, Romania0000-0003-2269-718XAliAkramDepartamento de Matematica-ICE, Universidade Federal de Amazonas-UFAM, 69080-900 Manaus0000-0002-6053-3031CătălinBarbu"Vasile Alecsandri" National College, str. Vasile Alecsandri nr. 37, Bacau, Romania0000-0002-2094-1938Journal Article20210118The scope of this paper is twofold. On the one hand, we will investigate the reversible geodesics of a Finsler space endowed with the deformed newly introduced (α,β)-metric<br /> <br /> begin{equation}<br />F_{ε}(α,β)=frac{β^{2}+α^{2}(a+1)}{α}+εβ<br />end{equation}<br />where ε is a real parameter with |ε|<2√a+1 and ain(¼,∞); and on the other hand, we will investigate the T-tensor for this metric.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201Ensuring software maintainability at software architecture level using architectural patterns81102427210.22060/ajmc.2021.19232.1044ENMohammadTanhaeiDepartment of Engineering, Ilam UniversityZahedRahmatiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranJournal Article20201107Software architecture is known to be an effective tool with regards to improving software quality attributes. <br />Many quality attributes such as maintainability are architecture dependent, and as such, using an appropriate architecture is essential in providing a sound foundation for the development of highly maintainable software systems. <br />An effective way to produce a well-built architecture is to utilize standard architectural patterns.<br />Although the use of a particular architectural pattern cannot have a preserving effect on software maintainability, the mere conformance of a system to any architecture cannot guarantee the system's high maintainability.<br />The use of an inappropriate architecture can seriously undermine software maintainability at lower levels. <br />In this article, the effect of standard architectural patterns on software maintainability quality attributes is investigated. <br />We develop a quality model for maintainability quality attributes, which is later used to compare various standard architectural patterns.<br />We finish by investigating two real-world experiences regarding the application of a particular pattern to two different existing architectures, exploring the effect of the change in architecture on maintainability quality attributes.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201On some aspects of measure and probability logics and a new logical proof for a theorem of Stone103108427310.22060/ajmc.2021.19318.1045ENAlirezaMofidiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranJournal Article20201202One of the functions of mathematical logic is studying mathematical objects and notions by logical means. There are several important representation theorems in analysis. Amongst them, there is a well-known classical one which concerns probability algebras. There are quite a few proofs of this result in the literature. This paper pursues two main goals. One is to consider some aspects of measure and probability logics and expose a novel proof for the mentioned representation theorem using ideas from logic and by application of an important result from model theory.<br />The second and even more important goal is to present more connections between two fields of analysis and logic and reveal more the strength of logical methods and tools in analysis. The paper is mostly written for general mathematicians, in particular the people who are active in analysis or logic as the main audience. It is self-contained and includes all prerequisites from logic and analysis.Amirkabir University of TechnologyAUT Journal of Mathematics and Computing2120210201The complexity of cost constrained vehicle scheduling problem109115427410.22060/ajmc.2021.19454.1046ENMaliheNiksiratDepartment of Computer Science, Faculty of Computer and Industrial Engineering, Birjand University of Technology, Birjand, IranSeyed NaserHashemiDepartment of Mathematics and Computer Science, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranJournal Article20210104This paper considered the cost constrained vehicle scheduling problem under the constraint that the total number of vehicles is known in advance. Each depot has a different time processing cost. The goal of this problem is to find a feasible minimum cost schedule for vehicles. A mathematical formulation of the problem is developed and the complexity of the problem when there are more than two depots is investigated. It is proved that in this case, the problem is NP-complete. Also, it is showed that there is not any constant ratio approximation algorithm for the problem, i.e., it is in the complexity class APX.