简介：WeconsiderdiffusivelimitoftheBoltzmannequationinaperiodicbox.WeestablishL~6estimateforthehydrodynamicpartPfofparticledistributionfunction,whichleadstouniformboundsglobalintime.

简介：LetMbeacompactorientable3-manifoldwithMconnected.IfV∪SWisaHeegaardsplittingofMwithdistanceatleast6,thenthe-stabilizationofV∪SWalongMisunstabilized.HenceMhasatleasttwounstabilizedHeegaardsplittingswithdifferentgenera.ThebasictoolisaresultondiskcomplexgivenbyMasurandSchleimer.

简介：Theaimofthispaperistostudy6-canonicalsystemofanonsigualrminimal3-foldX.If|2KX|isnotcomposedofpencils,itisshownthatΦ|6KX|isbirationalwithpossibleexceptionsfor:(K^3X,X(OX),ps(X))=(2,-1,1)or(4,-1,0)or(4,-1,1).

简介：InapaperbyZhangandChenetal.(see[11]),aconjecturewasmadeconcerningtheminimumnumberofcolorsXat(G)requiredinapropertotal-coloringofGsothatanytwoadjacentverticeshavedifferentcolorsets,wherethecolorsetofavertexvisthesetcomposedofthecolorofvandthecolorsincidenttov.WefindtheexactvaluesofXat(G)andthusverifytheconjecturewhenGisaGeneralizedHalingraphwithmaximumdegreeatleast6.AgeneralizedHalingraphisa2-connectedplanegraphGsuchthatremovingalltheedgesoftheboundaryoftheexteriorfaceofG(thedegreesoftheverticesintheboundaryofexteriorfaceofGareallthree)givesatree.

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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.

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简介：Inthispaper,wepresentatheoreticalanalysisforlinearfiniteelementsuperconvergentgradientrecoveryonPar6mesh,thedualofwhichiscentroidalVoronoitessellationswiththelowestenergyperunitvolumeandisthecongruentcellpredictedbythethree-dimensionalGersho'sconjecture.Weshowthatthelinearfiniteelementsolutionu_handthelinearinterpolationu_1havesuperclosegradientonPar6meshes.Consequently,thegradientrecoveredfromthefiniteelementsolutionbyusingthesuperconvergencepatchrecoverymethodissuperconvergentto▽u.Anumericalexampleispresentedtoverifythetheoreticalresult.

简介：Inthispaper,wediscusstheG-decompositionofλKv(G-GDλ(v))intofivegraphswithsixverticesandeightedges.WepresentsomerecursivestructuresandanumberofG-designsofsmallorders,holeyGdesigns,andincompleteG-designsareconstructed.Finally,thespectrumoftheexistenceofG-GDλ(v)isdetermined.

简介：ThechoicenumberofagraphG,denotedbyX1(G),istheminimumnumberksuchthatifalistofkcolorsisgiventoeachvertexofG,thereisavertexcoloringofGwhereeachvertexreceivesacolorfromitsownlistnomatterwhatthelistsare.Inthispaper,itisshowedthatX1(G)≤3foreachplanegraphofgirthnotlessthan4whichcontainsno6-,7-and9-cycles.

简介：<正>近几年来海南省关于轴对称、平移与旋转这方面的中考试题,常见的题型有选择题、填空题、网格作图题,主要考查的内容为轴对称、平移与旋转的基本性质.但在2014年的中考命题中,网格作图已不在是主要的考查方式,而是将旋转的有关内容与其它的几何内容相结合,变成一道综合性有点强的填空题,从而达

简介：证明了图2Kv的可旋转(4,6)圈系存在的充分必要条件为:v≥10,v≡0,5(mod10).更多还原

简介：<正>常见的图形运动有三种:轴对称、平移和旋转.这三种变换刻画了"两个全等图形"特定的位置关系,贯穿于三角形、四边形、圆等基本几何图形性质的研究.通过设置基于基本变换的试题,可以考查学生对基本图形本质的理解,又能考查学生的空间观念、动手操作、猜想验证

简介：<正>三角形的有关知识是"空间与图形"中最为核心的内容.它包括两类:一是基于一个三角形的知识,包括三角形各个元素之间的关系(边之间的关系、角之间的关系、边与角的关系),以及有关的重要线段(高线、中线、角平分线、中位线);二是基于三角形之间关系的知识,如两个三角形的全等关系(性质与判定)等.一、中考内容要求1.了解三角形的有关概念及各元素之间的关系,

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简介：假设调整法及应用绵竹大西街小学邓寒梅王传虎假设调整法是一种特殊的解题策略。把题目中的条件经假设进行推算，然后将假设条件下所得结果与题目中的已知条件进行对比，最后加以适当调整，即可求出正确结果。在我国古代算术中，解有关“鸡兔同笼问题”，“龟鹤问题”或“...

简介：1．《数学之友》2011年选题范围涉及：数学教育基本理论研究、中国数学教育传统及其特征研究、中小学数学课程与教学改革的实践研究、现代教育技术与数学教学改革、解题的理论与实践研究、中学生数学学习的心理研究等．