简介:InthispaperwegivesixexplicitformulaetocomputetheKirchhoffindex,themultiplicativedegree-Kirchhoffindexandtheadditivedegree-Kirchhoffindexofthek-cactuschainandthecactusgraphwhichcanbeobtainedfromak-cactuschainbyexpandingeachofthecut-verticestoacutedge.
简介:Westudythestructureofinvertiblesubstitutionsonthree-letteralphabet.Weshowthatthereexistsafi-nitesetSofinvertiblesubstitutionssuchthatanyinvertiblesubstitutioncanbewrittenasIwoσ1oσ2…σk,whereIwistheinnerautomorphismassociatedwithw,andσj∈Sforl≤j≤k.Asaconsequence,Misthematrixofaninvertiblesubstitutionifandonlyifitisafiniteproductofnon-negativeelementarymatrices.
简介:<正>Inthispaper,westudythebifurcationproblemsofroughheteroclinicloupscormectingthrecsaddlepointsforahigher-dimensionalsystem.Undersometransversalconditionsandthenontwistedcondition.theexistence.uniqueness.ndincoexistenccofthcl-heteroclinicloopwiththrecortwosaddlepomts.l-homoclinicorbitandl-periodicorbitnearTareobtained.Nleanwhile,thebifurcationsurfacesandexistenceregionsarealsogiven.Moreover.theabovebifurcationresultsareextendedtothecaseforheteroclinicloopwithlsaddlepoints.
简介:Considerathree-dimensionalsystemhavinganinvariantsurface.Byusingbifurcationtechniquesandanalyzingthesolutionsofbifurcationequations,theauthorsstudythespacialbifurcationphenomenaofakmultipleclosedorbitintheinvariantsurface.Thesufficientconditionsoftheexistenceofmanyclosedorbitsbifurcatefromthekmultipleclosedorbitareobtained.
简介:Thegas-kinetictheorybasedfluxsplittingmethodhasbeensuccessfullyproposedforsolvingone-andtwo-dimensionalidealmagnetohydrodynamicsbyXuetal.[J.Comput.Phys.,1999;2000],respectively.Thispaperextendsthekineticmethodtosolvethree-dimensionalidealmagnetohydrodynamicsequations,whereanadaptiveparameterηisusedtocontrolthenumericaldissipationinthefluxsplittingmethod.SeveralnumericalexamplesaregiventodemonstratethattheproposedmethodcanachievehighnumericalaccuracyandresolvestrongdiscontinuouswavesinthreedimensionalidealMHDproblems.
简介:Inthispaper,thenotionoftheboundedcompactapproximationproperty(BCAP)ofapair[Banachspaceanditssubspace]isusedtoprovethatifXisaclosedsubspaceofL∞withtheBCAP,thenL∞/XhastheBCAP.WealsoshowthatX*hastheλ-BCAPwithconjugateoperatorsifandonlyifthepair(X,Y)hastheλ-BCAPforeachfinitecodimensionalsubspaceY∈X.LetMbeaclosedsubspaceofXsuchthatM⊥iscomplementedinX*.IfXhasthe(bounded)approximationpropertyoforderp,thenMhasthe(bounded)approximationpropertyoforderp.
简介:TheauthorsdefinetheGaussmapofsurfacesinthethree-dimensionalHeisenberggroupandgivearepresentationformulaforsurfacesofprescribedmeancurvature.Furthermore,asecondorderpartialdifferentialequationfortheGaussmapisobtained,anditisshownthatthisequationisthecompleteintegrabilityconditionoftherepresentation.
简介:Inthispaper,anewnumericalmethodfortheSignoriniprobleminthree-dimensionalelasticityispresented.Theproblemisreducedtoaboundaryvariationalinequalitybasedonanewrepresentationofthederivativeofthedoublelayerpotential.Furthermore,aboundaryelementprocedureisdescribedforthenumericalapproximationofitssolutionandanabstracterrorestimateisgiven.