简介:WeproposethevariationaldescriptionofgeneratingfunctionapproachoffirstkindforHamil-tonianODEs,andextendtheapproachtothesemi-linearwaveequations.Inthisway,wecanconstructanyfiniteorderaccuracyscheme,andshowthattheresultingnumericalschemeismultisymplectic.Atlast,wepresentsomenumericalexperimentsbyusingderivednewscheme.
简介:Weproveconvergenceforameshfreefirst-ordersystemleastsquares(FOSLS)partitionofunityfiniteelementmethod(PUFEM).Essentially,byvirtueofthepartitionofunity,localapproximationgivesrisetoglobalapproximationinH(div)∩H(curl).TheFOSLSformulationyieldslocalaposteriorierrorestimatestoguidethejudiciousallotmentofnewdegreesoffreedomtoenrichtheinitialpointsetinameshfreedis-cretization.Preliminarynumericalresultsareprovidedandremainingchallengesarediscussed.
简介:ThispaperdevelopsaclaseofquadratureformulawithfirstderivativesItisdemonstratedthatitsdegreeofaccuracyisnotlessthan2k+1forasetofdistinctnodes{x0,x1,...,xn}overinterval[a,b],andjustonly2k+1forequallyspacednodes.FarovercomingtheshortcomingofinvolvingagreatnumberofmanualcomputationsfortheintegrationrulesoftheHermitianinterpolationformula,somesimpleformulasforcomputingautomaticallyβi,γiandE[f]bycomputeraregiven,especiallyforequallyspacednodes.
简介:§1.IntroductionItisknownthatthefollowingCauchyproblemforaparabolicpartialdifferentialequation(wherethevaluesattherightboundary,u.(1,t)=v(t)areunknownandsoughtfor)isill-posed:thesolution(v)doesnotdependcontinuouslyonthedata(g).Inordertotreattheill-posednessanddevelopthenumericalmethod,onereformulatestheproblemasaVolterraintegralequationofthefirstkindwishaconvolutiontypekernel(seeSneddon[1],CarslawandJaeger[2])
简介:1.IntroductionConsiderthefirstorderdifferentialequationwithdeviatingargUmelltTheoscillationofEq.(1)wasstudiedextensivelyinthelastthreedecades.See,forexamDleif--101andthereferencescitedtherein.In1972Ladas.LakshlnhanthamanddeceivedApril1,1997.Re~AugUBt...
简介:ByadoptinganiceauxiliarytransformofMarkovoperators,wederivenewboundsforthefirsteigenvalueofthegeneratorcorrespondingtosymmetricMarkovprocesses.Ourresultsnotonlyextendtherelatedtopicintheliterature,butalsoareefficientlyusedtostudythefirsteigenvalueofbirth-deathprocesseswithkillingandthatofellipticoperatorswithkillingonhalfline.Inparticular,weobtaintwoapproximationproceduresforthefirsteigenvalueofbirth-deathprocesseswithkilling,andpresentqualitativelysharpupperandlowerboundsforthefirsteigenvalueofellipticoperatorswithkillingonhalfline.
简介:TheauthorgivesanoptimumestimateofthefirsteigenvalueofacompactRiemannianmanifold.ItisshownthatletMbeacompactRiemannianmanifold,thenthefirsteigenvalueλ1oftheLaplaceoperatorofMsatisfiesα1+max{0,-(n-1)K}≥π2/d2wheredisthediameterofMand(n-1)KisthenegativelowerboundoftheRiccicurvatureofM.
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.
简介:Thispaperconcernswithexistenceofgeneralizedsolutionsoffirstboundaryvalueproblemforakindofstronglydegeneratequasilinearparabolicequations.TheauthorassumesthatthecoefficientsintheequationsatisfystronglydegeneratemonotoneconditionandotherweakenedconditionscomparingwiththoseofLadyzenskaja’s.Anexistencetheoremisgivenandproved.
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.
简介:Theinitialvalueproblemsandthefirstboundaryproblemsforthequasilinearwaveequationutt-[a0+na1(ux)n-1]uxx-a2uxxtt=0areconsidered,wherea0,a2>0areconstants,a1isanarbitraryrealnumber,nisanaturalnumber.Theexistenceanduniquenessoftheclassicalsolutionsfortheinitialvalueproblemsandthefirstboundaryproblemsoftheequation(1)areprovedbytheGalerkinmethod.
简介:Inthispaper,wenotonlyconstructtheconfidenceregionforparametersinamixedinteger-valuedautoregressiveprocessusingtheempiricallikelihoodmethod,butalsoestablishtheempiricallog-likelihoodratiostatisticandobtainitslimitingdistribution.Andthen,viasimulationstudieswegivecoverageprobabilitiesfortheparametersofinterest.Theresultsshowthattheempiricallikelihoodmethodperformsverywell.