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28 个结果
  • 简介:WeproposethevariationaldescriptionofgeneratingfunctionapproachoffirstkindforHamil-tonianODEs,andextendtheapproachtothesemi-linearwaveequations.Inthisway,wecanconstructanyfiniteorderaccuracyscheme,andshowthattheresultingnumericalschemeismultisymplectic.Atlast,wepresentsomenumericalexperimentsbyusingderivednewscheme.

  • 标签: GENERATING FUNCTION method inultisyrnplectic VARIATIONAL DESCRIPTION
  • 简介:Weproveconvergenceforameshfreefirst-ordersystemleastsquares(FOSLS)partitionofunityfiniteelementmethod(PUFEM).Essentially,byvirtueofthepartitionofunity,localapproximationgivesrisetoglobalapproximationinH(div)∩H(curl).TheFOSLSformulationyieldslocalaposteriorierrorestimatestoguidethejudiciousallotmentofnewdegreesoffreedomtoenrichtheinitialpointsetinameshfreedis-cretization.Preliminarynumericalresultsareprovidedandremainingchallengesarediscussed.

  • 标签: 适应有限元 最小方程式 数学模型 计算数学
  • 简介:ThispapergivesacharacterizationofaHuntprocesspathbythefirstexitleftlimitdistribution.Itisalsoshowedthatifthefirstexitleftlimitdistributionleavinganyballfromthecenterisauniformdistributiononthesphere,thentheL'evyProcessesareascaledBrownianmotion.

  • 标签: 出口 连续性 路径 分配 极限分布 均匀分布
  • 简介:ThispaperdevelopsaclaseofquadratureformulawithfirstderivativesItisdemonstratedthatitsdegreeofaccuracyisnotlessthan2k+1forasetofdistinctnodes{x0,x1,...,xn}overinterval[a,b],andjustonly2k+1forequallyspacednodes.FarovercomingtheshortcomingofinvolvingagreatnumberofmanualcomputationsfortheintegrationrulesoftheHermitianinterpolationformula,somesimpleformulasforcomputingautomaticallyβi,γiandE[f]bycomputeraregiven,especiallyforequallyspacednodes.

  • 标签: QUADRATURE FORMULA DEGREE of accuracy.
  • 简介:在这份报纸,为有海森堡组上的重量的第一顺序插值不平等的足够、必要的条件被给。必要性被海森堡组的极的坐标变化讨论。由插值为功能和Hardy-Sobolev类型不平等经由一个新表示公式建立强壮的类型不平等的一个班,我们导出充足。最后,为强壮的类型不平等的锋利的常数是坚定的。

  • 标签: HEISENBERG群 HARDY型不等式 插值 一阶 重量 充分必要条件
  • 简介:§1.IntroductionItisknownthatthefollowingCauchyproblemforaparabolicpartialdifferentialequation(wherethevaluesattherightboundary,u.(1,t)=v(t)areunknownandsoughtfor)isill-posed:thesolution(v)doesnotdependcontinuouslyonthedata(g).Inordertotreattheill-posednessanddevelopthenumericalmethod,onereformulatestheproblemasaVolterraintegralequationofthefirstkindwishaconvolutiontypekernel(seeSneddon[1],CarslawandJaeger[2])

  • 标签: FIRST posed KERNEL CONVOLUTION sought PARABOLIC
  • 简介:1.IntroductionConsiderthefirstorderdifferentialequationwithdeviatingargUmelltTheoscillationofEq.(1)wasstudiedextensivelyinthelastthreedecades.See,forexamDleif--101andthereferencescitedtherein.In1972Ladas.LakshlnhanthamanddeceivedApril1,1997.Re~AugUBt...

  • 标签: OSCILLATION DIFFERENTIAL EQUATION deviating ARGUMENT
  • 简介:ByadoptinganiceauxiliarytransformofMarkovoperators,wederivenewboundsforthefirsteigenvalueofthegeneratorcorrespondingtosymmetricMarkovprocesses.Ourresultsnotonlyextendtherelatedtopicintheliterature,butalsoareefficientlyusedtostudythefirsteigenvalueofbirth-deathprocesseswithkillingandthatofellipticoperatorswithkillingonhalfline.Inparticular,weobtaintwoapproximationproceduresforthefirsteigenvalueofbirth-deathprocesseswithkilling,andpresentqualitativelysharpupperandlowerboundsforthefirsteigenvalueofellipticoperatorswithkillingonhalfline.

  • 标签: 第一特征值 马氏过程 对称 应用 夏普 生灭过程
  • 简介:TheauthorgivesanoptimumestimateofthefirsteigenvalueofacompactRiemannianmanifold.ItisshownthatletMbeacompactRiemannianmanifold,thenthefirsteigenvalueλ1oftheLaplaceoperatorofMsatisfiesα1+max{0,-(n-1)K}≥π2/d2wheredisthediameterofMand(n-1)KisthenegativelowerboundoftheRiccicurvatureofM.

  • 标签: RIEMANNIAN EIGENVALUE RICCI MANIFOLD curvature Laplace
  • 简介:在这篇文章,我们学习在联合起来的范围在一个领域上弄弯问题的更高的顺序的开始的二个特征值。我们以第一个特征值在第二个特征值上获得估计。特别地,弄弯黄,李和Qi的问题的更高的顺序的开始的二个特征值上的估计[5]在我们的结果被包括。

  • 标签: 特征值估计 球形 第一特征值 单位球 屈曲 高阶
  • 简介:Inthispaper,thefirstboundaryvalueproblemforquasilinearequationoftheform△A(u,x)+m∑i=1(e)bi(u,x)/(e)xi+c(u,x)=0,Au(u,x)≥0isstudied.Byusingthecompensatedcompactnesstheory,someresultsontheexistenceofweaksolutionareestablished.Inaddition,undercertainconditiontheuniquenessofsolutionisproved.

  • 标签: 准线性退化椭圆方程 边值问题 弱解 存在性 唯一性
  • 简介:本文通过对工科院校科技英语专业高等数学采用美国耶鲁大学SergeLang编的“AFirstCourseinCalculus”原版教材的教学实践,对该教材的第四版和第五版的基本结构有了比较全面深入的了解,特别是分析研究了该书的突出待点,并对几个具体问题的处理进行了阐述。

  • 标签: 工科数学 定积分 美国耶鲁大学 初等函数 英语专业 高阶导数
  • 简介:Thispaperconcernswithexistenceofgeneralizedsolutionsoffirstboundaryvalueproblemforakindofstronglydegeneratequasilinearparabolicequations.TheauthorassumesthatthecoefficientsintheequationsatisfystronglydegeneratemonotoneconditionandotherweakenedconditionscomparingwiththoseofLadyzenskaja’s.Anexistencetheoremisgivenandproved.

  • 标签: DEGENERATE MONOTONE parabolic satisfy FIRST weakened
  • 简介:Inthispapertheexistenceresultsofpositiveω-periodicsolutionsareobtainedforsecondorderordinarydifferentialequation-u″(t)=f(t,u(t))(t∈R),andalsoforfirstorderordinarydifferentialequationu′(t)=f(t,u(t))(t∈R),wheref:R×R+→Risacontinuousfunctionwhichisω-periodicint.Thediscussionisbasedonthefixedpointindextheoryincones.

  • 标签: 正周期解 微分方程 圆锥体 不动点指数
  • 简介:Thispaperstudiesfirstordersemilinearhyperbolicsystemsinn(n≥2)spacedimensions.Underthehypothesisthatthesystemsatisfiessocalled‘nullcondition',thelocalwell-posednessforitsCauchyproblemwithinitialdatainH^(n-1)/2isproved.

  • 标签: 半线性系统 CAUCHY问题 初值数据 双曲线方程
  • 简介:Theinitialvalueproblemsandthefirstboundaryproblemsforthequasilinearwaveequationutt-[a0+na1(ux)n-1]uxx-a2uxxtt=0areconsidered,wherea0,a2>0areconstants,a1isanarbitraryrealnumber,nisanaturalnumber.Theexistenceanduniquenessoftheclassicalsolutionsfortheinitialvalueproblemsandthefirstboundaryproblemsoftheequation(1)areprovedbytheGalerkinmethod.

  • 标签: QUASILINEAR wave equations INITIAL value PROBLEMS
  • 简介:WestudythestructureofBernstein’sfirstsummableoperatorsandshowthattheycon-vergeuniformlytocontinuonsfunctionsonthespecialrealorthogonalgroupSO(n)inthispaper.Inaddition,wehavealsodiscussedtheapproximationdegreetoaclassoffunctionLipα(0<α≤1)onSO(n).

  • 标签: OPERATORS verge FIRST REAL UNIFORMLY kernel
  • 简介:Inthispaper,wenotonlyconstructtheconfidenceregionforparametersinamixedinteger-valuedautoregressiveprocessusingtheempiricallikelihoodmethod,butalsoestablishtheempiricallog-likelihoodratiostatisticandobtainitslimitingdistribution.Andthen,viasimulationstudieswegivecoverageprobabilitiesfortheparametersofinterest.Theresultsshowthattheempiricallikelihoodmethodperformsverywell.

  • 标签: mixed integer-valued AUTOREGRESSIVE model empirical LIKELIHOOD