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196 个结果
  • 简介:已知曲线Γ:r=r(s)的基本向量α、β、γ且曲率和挠率分别为κ、τ,本文研究了由α、β和γ所作出的曲线Γ:ρ=r+αa+b∫s0^sβds的曲率κ和挠率τ的计算问题。

  • 标签: 曲线 曲率 挠率 基本向量
  • 简介:Theobjectiveofthispaperistointroduceelementarydiscretereflectedbackwardequationsandtogiveasimplemethodtodiscretizeintimea(continuous)reflectedbackwardequation.Apresentationofnumericalsimulationsisalsodescribed.

  • 标签: 反射方程 逆向方程 弱收敛 离散化
  • 简介:ThispaperdealswiththeexistenceandmultiplicityofperiodicsolutionsofDuffingequationsx+g(x)=p(t),TheauthorprovesaninfinityofperiodicsolutionstotheperiodicallyforcednonlinearDuffingequationsprovidedthatg(z)satisfiesthegloballylipschitzianconditionandthetime-mappingsatisfiestheweakeroscillatingproperty.

  • 标签: 周期解 重数 达芬方程 利普希茨条件
  • 简介:在这份报纸,我们学习(伪,分级的旗帜弯曲在上的尾)度量标准一歧管尺寸n的M(n鈮?3)。建议那一(伪,尾)度量标准F不是Randers类型的一个Finsler度量标准,也就是说F鈮吗?+k3尾k1>0,k2并且k3是M上的分级的功能。如果并且仅当,我们证明F具有分级的旗帜弯曲并且消失的S弯曲旗帜弯曲K=0并且F是一个Berwald度量标准。在这种情况中,F是一局部地Minkowski度量标准。关键词Finsler度量标准-(伪,尾)度量标准-旗帜弯曲-S弯曲-Minkowski公制的先生(2000)题目分类53B40-53C60由中国(资助号码10971239)的国家自然科学基础支持了

  • 标签: 曲率度量 标量函数 常数 闵可夫斯基 旗曲率 兰德斯
  • 简介:本文,首先在V.V.Stepanov空间连续模概念,在此空间内讨论概周期函数的Fourier系数与连续模之间的关系。

  • 标签: S^p空间 连续模 概周期函数 傅里叶系数
  • 简介:Byusingsequentiallylowercompletespaces(see[Zhu,J.,Wei,L.,Zhu,C.C.:Caristitypecoincidencepointtheoremintopologicalspaces.J.AppliedMath.,2013,ID902692(2013)]),wegiveanewversionofvectorialEkeland’svariationalprinciple.Inthenewversion,theobjectivefunctionisdefinedonasequentiallylowercompletespaceandtakingvaluesinaquasi-orderedlocallyconvexspace,andtheperturbationconsistsofaweaklycountablycompactsetandanon-negativefunctionpwhichonlyneedstosatisfyp(x,y)=0iffx=y.Here,thefunctionpneednotsatisfythesubadditivity.FromthenewEkeland’sprinciple,wededuceavectorialCaristi’sfixedpointtheoremandavectorialTakahashi’snon-convexminimizationtheorem.Moreover,weshowthattheabovethreetheoremsareequivalenttoeachother.Byconsideringsomeparticularcases,weobtainanumberofcorollaries,whichincludesomeinterestingversionsoffixedpointtheorem.

  • 标签: EKELAND变分原理 拓扑空间 CARISTI不动点定理 重合点定理 Caristi型 目标函数
  • 简介:LetEbeacompacts-setsofR^n,TheauthorsdefineanorthonormalsystemФoffunctionsonEandobtainthat,foranyf(x)∈L^l(E1H^8),theFourierseriesoff1withrespecttoФ,isequaltof(x)atH^8-a.e-x∈E.Moreover,foranyf∈L^p(E,H^8)(p≥1),thepartialsumsoftheFourierseries,withrespecttoФ,offconvergestofinL^P-norm.

  • 标签: HAUSDORFF测度 FOURIER级数 S集 广义性
  • 简介:WepressentnewKyFantypebestapproximationtheoremsforadiscontinuousmultivaluedmaponmetrizabletopologicalvectorspacesandhyperconvexspaces.Inaddition,fixedpointresultsarederivedforthemapstudied.Ourworkgeneralizesseverlresultsinapproximationtheory.

  • 标签: 近似值 定理 可度量化 向量空间
  • 简介:ThenonconformingWilson’sbrickclassicallyisrestrictedtoregularhexahedralmeshes.LesaintandZlamal[6]relaxedthisconstraintforthetwo-dimensionalanalonueofthiselementInthispaperweextendtheirresultstothreedimensionsandprovethatandwhereuistheexactsolution,u_histheapproximatesolutionandistheusualnormfortheSobolevspaceH~1(?).

  • 标签: CONVERGENCE NONCONFORMING Wilson’s BRICK hexahedral meshes.
  • 简介:ThispapergivesatutorialonhowtoproveLyapunovtypecriteriabyoptimalcontrolmethods.Firstly,weconsiderstabilitycriteriaonHill'sequationswithnonnegativepotential.Byoptimalcontrolmethodsdevelopedin1990s,weobtainseveralstabilitycriteriaincludingLyapunov'scriterion,Ne..gauzandLidski'scriterion.Secondly,wepresentstabilitycriteriaonHill'sequationswithsign-changingpotentialinwhichBrog'scriterionandKrein'scriterionareincluded.

  • 标签: stability CRITERIA optimal control method Hill's