فهرست مطالب mehran namjoo
-
In this paper, we introduce the notion of T-conformal transformations and T-conformal maps between Riemannian manifolds. Here, T stands for a smooth (1,1)-tensor field defined on the domain of these maps. We start by defining what it means for a map to be T-conformal and also dwell on some basic properties of such type maps. We next specialize our discussion to the situation when the map T satisfies the condition ∇T = 0. Accordingly, we prove Liouville's theorem for T-conformal maps between space forms Rn(c) as an application under the condition ∇T = 0. The proof relies upon properties of T-conformal maps proved earlier. Broadly, the paper seeks to provide a general understanding of conformal mappings in the presence of a tensor field T and show how classical results such as Liouville's theorem apply.Keywords: Conformal Map, Isometry, (1, 1) --Tensor Field}
-
هدف از این مقاله، بررسی عملگر شکلی یک توزیع $ (n-1) $-بعدی روی یک خمینه $ n $-بعدی هموار است. در این مطالعه ابتدا فرمول هایی را برای عملگر شکلی و مولفه های متقارن و پادمتقارن آن ارائه می کنیم و در ادامه ارتباط آن ها با مفاهیمی مانند انتگرال پذیری، تماما نافی و ژئودزیک را نشان می دهیم. سرانجام، با درنظر گرفتن حداکثر دو مقدار ویژه برای عملگر شکلی، به دسته بندی این توزیع ها و برگ بندی آنها در فضافرم های ساده همبند می پردازیم.
کلید واژگان: توزیع, عملگر شکلی, فرم اساسی دوم}This paper aims to study of shape operator of an -dimensional distribution on an -dimensional smooth manifold. In this study firstly we state formulae for the shape operator and its symmetric and anti-symmetric components and in continuation we show their relationships with some notions such as integrability, totally umbilic and totally geodesic. Finally, by considering at most two eigenvalues for the shape operator, we classify this distribution and their foliations in simply connected space forms.
Keywords: Distribution, Shape Operator, Second Fundamental Form} -
The aim of this manuscript is to introduce and analyze a stochastic finite difference scheme for Ito stochastic partial differential equations. We also discuss the consistency, stability, and convergence for the stochastic finite difference scheme. The numerical simulations obtained from the proposed stochastic finite difference scheme show the efficiency of the suggested stochastic finite difference scheme.
Keywords: Stochastic partial differential equations, Stochastic finite difference scheme, Stability, Consistency, Convergence} -
In this paper we classify proper $L_k$-biharmonic hypersurfaces $ M $, in the unit Euclidean sphere which has two principal curvatures and we show that they are open pieces of standard products of spheres. Also we study proper $L_k$-biharmonic compact hypersurfaces $ M $ with respect to $tr(S^2circ P_k)$ and $ H_k $ where $ S $ is the shape operator, $ P_k $ is the Newton transformation and $ H_k $ is the $ k $-th mean curvature of $ M $, and by definiteness's assumption of $ P_k $, we show that $ H_{k+1} $ is constant.Keywords: L, k operator, biharmonic hypersurfaces, Chen conjecture}
-
In this paper, an implicit finite difference scheme is proposed for the numerical solution of stochastic partial differential equations (SPDEs) of Ito type. The consistency, stability and convergence of the scheme is analyzed. Numerical experiments are included to show the efficiency of the scheme.Keywords: Stochastic partial differential equations, Stochastic finite difference scheme, Stability, Consistency, Convergence}
-
In this paper, a high-order and conditionally stable stochastic difference scheme is proposed for the numerical solution of Ito^ stochastic advection diffusion equation with one dimensional white noise process. We applied a finite difference approximation of fourth-order for discretizing space spatial derivative of this equation. The main properties of deterministic difference schemes, i.e. consistency, stability and convergence, are developed for the stochastic case. It is shown through analysis that the proposed scheme has these properties. Numerical results are given to demonstrate the computational efficiency of the stochastic scheme.Keywords: stochastic partial differential equations, consistency, Stability, convergence}
-
Iranian Journal of Numerical Analysis and Optimization, Volume:6 Issue: 1, Winter and Spring 2016, PP 53 -79ýýIn this paperý, ýwe introduce fractional-order for a model of tritrophic food chain Lotka-Volterraý. ýMoreoverý, ýwe discuss the stability analysis of fractional systemý. ýThe nonstandard finite difference (NSFD) scheme is implementedý ýto study the dynamic behaviors in the fractional-order Lotka-Volterra systemý. ýNumerical results show that theý ýNSFD approach is easy to implement and accurate when applied to fractional -order Lotka-Volterra systemý.Keywords: Fractional differential equations, Lotka, Volterra model, prey, predator system, Nonstandard finite difference scheme, ý ýStability}
-
Iranian Journal of Numerical Analysis and Optimization, Volume:5 Issue: 1, Winter and Spring 2015, PP 1 -12In this paper, a class of semi-implicit two-stage stochastic Runge-Kutta methods (SRKs) of strong global order one, with minimum principal error constants are given. These methods are applied to solve Itô stochastic differential equations (SDEs) with a Wiener process. The efficiency of this method with respect to explicit two-stage Itô Runge-Kutta methods (IRKs), It method, Milstien method, semi-implicit and implicit two-stage Stratonovich Runge-Kutta methods are demonstrated by presenting some numerical results.Keywords: Stochastic differential equations, Strong approximation, Runge, Kutta methods}
-
Iranian Journal of Numerical Analysis and Optimization, Volume:3 Issue: 1, Winter and Spring 2013, P 55R. Ewing, O. Liev, R. Lazarov and A. Naumovich in [1] proposed a finite volume discretization for one dimensional Biot poroelasticity system in multilayer domains. Their discretization and exact solution are invalid. We derive valid discretization and exact solution. Finally, our numerical solution is compared with known exact solution in discrete L2 norm.Keywords: Biot poroelasticity system, Interface problem, Finite volume discretization}
- در این صفحه نام مورد نظر در اسامی نویسندگان مقالات جستجو میشود. ممکن است نتایج شامل مطالب نویسندگان هم نام و حتی در رشتههای مختلف باشد.
- همه مقالات ترجمه فارسی یا انگلیسی ندارند پس ممکن است مقالاتی باشند که نام نویسنده مورد نظر شما به صورت معادل فارسی یا انگلیسی آن درج شده باشد. در صفحه جستجوی پیشرفته میتوانید همزمان نام فارسی و انگلیسی نویسنده را درج نمایید.
- در صورتی که میخواهید جستجو را با شرایط متفاوت تکرار کنید به صفحه جستجوی پیشرفته مطالب نشریات مراجعه کنید.