简介:TheConwaypotentialfunction(CPF)forcoloredlinksisaconvenientversionofthemultivariableAlexander–Conwaypolynomial.WegiveaskeincharacterizationofCPF,muchsimplerthantheonebyMurakami.Inparticular,Conway’s"smoothingofcrossings"isnotintheaxioms.Theproofusesareductionschemeinatwistedgroup-algebraP_nB_n,whereB_nisabraidgroupandP_nisadomainofmulti-variablerationalfractions.Theproofdoesnotusecomputeralgebratools.Aninterestingby-productisacharacterizationoftheAlexander–Conwaypolynomialofknots.
简介:Inthispaper,thecycle’sstructureofembeddedgraphsinsurfacesarestudied.Accordingtothemethodoffundamentalcycles,thesetC(Ccontainsallshortest)isfound.AundirectedgraphGwithnverticeshasatmostO(n5)manyshortestcycles;IftheshortestcycleofGisoddcycle,thenGhasatmostO(n3)manyshortestcycles;IfGhasbeenembeddedinasurfaceSg(Ng,gisaconstant),thenithasatmostO(n3)shortestcycles,moreover,iftheshortestcycleofGisoddcycle,then,GhasatmostO(n2)manyshortestcycles.WecanfindacyclebaseofG,thenumberofoddcyclesofG,thenumberofevencyclesofG,thenumberofcontractiblecyclesofG,thenumberofnon-contractiblecyclesofG,arealldecided.IftheΠ-embeddedgraphGhasΠ-twosidedcycles,then,CcontainsashortestΠ-twosidedcycleofG,thereisapolynomiallyboundedalgorithmthatfindsashortestΠ-twosidedcycleofaΠ-embeddedgraphG,thenewandsimplesolutionsabouttheopenproblemofBojanMoharandCarstenThomassenareobtained.
简介:Thispaperproposesaformallystrongerset-valuedClaxke'sfixedpointtheorem.Bythis-theoremwecanimproveafixedpointtheoremforweaklyinwardcontractionset-valuedmappingofD.DowingandW.A.Kirk.
简介:Byusingthefundamentalequationsofaxisymmetricshallowshellsofrevolution,thenonlinearbendingofashallowcorrugatedshellwithtaperunderarbitraryloadhasbeeninvestigated.ThenonlinearboundaryvalueproblemofthecorrugatedshellwasreducedtothenonlinearintegralequationsbyusingthemethodofGreen'sfunction.Tosolvetheintegralequations,expansionmethodwasusedtoobtainGreen'sfunction.ThentheintegralequationswerereducedtotheformwithdegeneratecorebyexpandingGreen'sfunctionasseriesofcharacteristicfunction.Therefore,theintegralequationsbecomenonlinearalgebraicequations.Newton'siterativemethodwasutilizedtosolvethenonlinearalgebraicequations.Toguaranteetheconvergenceoftheiterativemethod,deflectionatcenterwastakenascontrolparameter.Correspondingloadswereobtainedbyincreasingdeflectiononebyone.Asanumericalexample,elasticcharacteristicofshallowcorrugatedshellswithsphericaltaperwasstudied.Calculationresultsshowthatcharacteristicofcorrugatedshellschangesremarkably.Thesnappinginstabilitywhichisanalogoustoshallowsphericalshellsoccurswithincreasingloadifthetaperisrelativelylarge.Thesolutionisclosetotheexperimentalresults.
简介:AradialfunctioncanbeexpressedbyitsgeneratorthroughThepositivedefiniteofthefunctionplaysanimportantroteintheradialbasisinterpolation.WecannaturallyuseBochner’sTheoremtocheckifispositivedefinite.Thisrequireshoweveran-dhnensiotialFouriertransformationanditisnotveryeasytocalculate.Furthermoreinalotofcaseswewilluseforspacesofvariousdimensionstoo,thenforeveryfixednweneeddotheFouriertransformationoncetocheckifthefunctionispositivedefiniteinthen-di-mensionalspace.Thecompletelymonotonefunction:,whichisdiscussedin[4]ispositivedefiniteforarbitraryspacedimensions.Withthistechniquetvecanveryeasilycharacterizethepositivedefinite,ofaradialfunctionthroughitsgenerator.Unfortunatelythereisonlyaverysmallsubsetofradialfunctionwhichiscompletelymonotone.Thusthiscriterionexcludedalotofinterestingfunctionssuchascompactlysupportedradialfunction,whcihareveryusefulinapplic
简介:WeconductedtheresearchonthecalculationoftheJordannormalformofamatrixfrom1993to1998.Inthisperiod,weobtainedsometheoreticalresults,alsodevelopedandimplementedaseriesofalgorithmsforthetheoreticalresults.Nowthisresearchiscompletedtosomedegree.TheGolub-Wilkinson’sProblemComputingtheJordandecompositionofamatrix,introducedbyG.H.GolubandJ.
简介:Mardia(1970)definedameasureofmultivariatekurtosisandderiveditsasymptoticdistributionforsamplesfromamultivariatenormalpopulation.SomenewresultsonellipticaldistributionsareusedtoextendMardia’sresultstosamplesfromanellipticaldistribution.Theseresultsprovideamethodfortestinghypothesesonthekurtosisparameterofellipticaldistributions.AnappendixprovidesextensionsofKendallandStuart’s(1977)standarderrorsofbivariatemomentstothethirdandfourthorder.
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简介:AhighlyefficienttotalsynthesisofS-(+)-tylophorinehasbeenaccomplishedinfullyasymmetricfashion.
简介:ExplicitexpressionsofMori-Tanaka’stensorforatransverselyisotropicfiberreinforcedUDcompositearepresented.Closed-formformulaefortheeffectiveelasticpropertiesofthecompositeareobtained.Ina3Dsense,theresultingcompliancetensorofthecompositeissymmetric.Nevertheless,the2DcompliancetensorbasedonadeterioratedMori-Tanaka’stensorisnotsymmetric.Noristhecompliancetensordefineduponadeteriorated2DEshelby’stensor.Thein-planeeffectiveelasticpropertiesgivenbythosethreeapproachesaredifferent.AdetailedcomparisonbetweenthepredictedresultsobtainedfromthoseapproacheswithexperimentaldataavailableforanumberofUDcompositesismade.更多还原
简介:对于圆锥型和棱锥型Hamiltonian的Eikonal型方程,本文给出了一种几何方法,得出其初值问题解的表达式并且说明由此式给出的解为原初值问题的粘性解.首先用一个凸函数序列逼近Eikonal型方程中的Hamiltonian,再由Hopf-Lax公式给出方程序列的粘性解,最后证明了该粘性解序列会收敛到Eikonal方程的粘性解.
简介:用变分方法得到一类非线性差分方程多重周期解的存在性.我们的结果推广了Cai,Yu和Guo[Comput.Math.Appl.,52(2006),1630-1647]的结果,并且这里给出的证明显著地简化了.
简介:建立了一维p-laplacian方程(1)的一切解均为非振动的必要条件.所得定理改进了Kusano等在文[4]中的相应结果.