简介:LetMbeacompactorientable3-manifoldwithMconnected.IfV∪SWisaHeegaardsplittingofMwithdistanceatleast6,thenthe-stabilizationofV∪SWalongMisunstabilized.HenceMhasatleasttwounstabilizedHeegaardsplittingswithdifferentgenera.ThebasictoolisaresultondiskcomplexgivenbyMasurandSchleimer.
简介:InapaperbyZhangandChenetal.(see[11]),aconjecturewasmadeconcerningtheminimumnumberofcolorsXat(G)requiredinapropertotal-coloringofGsothatanytwoadjacentverticeshavedifferentcolorsets,wherethecolorsetofavertexvisthesetcomposedofthecolorofvandthecolorsincidenttov.WefindtheexactvaluesofXat(G)andthusverifytheconjecturewhenGisaGeneralizedHalingraphwithmaximumdegreeatleast6.AgeneralizedHalingraphisa2-connectedplanegraphGsuchthatremovingalltheedgesoftheboundaryoftheexteriorfaceofG(thedegreesoftheverticesintheboundaryofexteriorfaceofGareallthree)givesatree.
简介:LetP(G,λ)bethechromaticpolynomialofagraphG.TwographsGandHaresaidtobechromaticallyequivalent,denotedG~H,ifP(G,λ)=P(H,λ).Wewrite[G]={H|H~G}.If[G]={G},thenGissaidtobechromaticallyunique.Inthispaper,wefirstcharacterizecertaincomplete6-partitegraphswith6n+1verticesaccordingtothenumberof7-independentpartitionsofG.Usingtheseresults,weinvestigatethechromaticityofGwithcertainstarormatchingdeleted.Asaby-product,manynewfamiliesofchromaticallyuniquecomplete6-partitegraphswithcertainstarormatchingdeletedareobtained.
简介:GeneralizedSteiriertriplesystems,GS(2,3,n,g),areequivalenttomaximumconstantweightcodesoveranalphabetofsizeg+1withdistance3andweight3inwhicheachcodewordhaslengthn.ThenecessaryconditionsfortheexistenceofaGS(2,3,n,g)are(n-1)g≡0(mod2),n(n-1)g2≡0(mod6),andn≥g+2.Thesenecessaryconditionsareshowntobesufficientbyseveralauthorsfor2≤g≤11.Inthispaper,threenewresultsareobtained.First,itisshownthatforanygiveng,g≡0(mod6)andg≥12,ifthereexistsaGS(2.3.n.g)foralln,g+2≤n≤7g+13.thenthenecessaryconditionsarealsosufficient.Next,itisalsoshownthatforanygiveng,g≡3(mod6)andg≥15,ifthereexistsaGS(2,3,n,g)foralln,n≡1(mod2)andg+2≤n≤7g+6,thenthenecessaryconditionsarealsosufficient.Finally,asanapplication,itisprovedthatthenecessaryconditionsfortheexistenceofaGS(2,3,n,g)arealsosufficientforg=12,15.
简介:Inthispaper,wepresentatheoreticalanalysisforlinearfiniteelementsuperconvergentgradientrecoveryonPar6mesh,thedualofwhichiscentroidalVoronoitessellationswiththelowestenergyperunitvolumeandisthecongruentcellpredictedbythethree-dimensionalGersho'sconjecture.Weshowthatthelinearfiniteelementsolutionu_handthelinearinterpolationu_1havesuperclosegradientonPar6meshes.Consequently,thegradientrecoveredfromthefiniteelementsolutionbyusingthesuperconvergencepatchrecoverymethodissuperconvergentto▽u.Anumericalexampleispresentedtoverifythetheoreticalresult.
简介:给出三个非常容易让人误以为真的测度猜想,通过定理与λ-Cantor集及其余集的构造给出三个猜想的否定答案.
简介:ThechoicenumberofagraphG,denotedbyX1(G),istheminimumnumberksuchthatifalistofkcolorsisgiventoeachvertexofG,thereisavertexcoloringofGwhereeachvertexreceivesacolorfromitsownlistnomatterwhatthelistsare.Inthispaper,itisshowedthatX1(G)≤3foreachplanegraphofgirthnotlessthan4whichcontainsno6-,7-and9-cycles.