简介:<正>Foranoddfunctionf(x)definedonlyonafiniteinterval,thispaperdealswiththeexistenceofperiodicsolutionsandthenumberofsimpleperiodicsolutionsofthedifferentialdelayequation(DDE)(?)(t)=-f(x(t-1)).Byuseofthemethodofqualitativeanalysiscombinedwiththeconstructingofspecialsolutionsaseriesofinterestingresultsareobtainedontheseproblems.
简介:AgraphGiscalledchromatic-choosableifitschoicenumberisequaltoitschromaticnumber,namelych(G)=χ(G).Ohba’sconjecturestatesthateverygraphGwith2χ(G)+1orfewerverticesischromaticchoosable.ItisclearthatOhba’sconjectureistrueifandonlyifitistrueforcompletemultipartitegraphs.Recently,Kostochka,StiebitzandWoodallshowedthatOhba’sconjectureholdsforcompletemultipartitegraphswithpartitesizeatmostfive.Butthecompletemultipartitegraphswithnorestrictionontheirpartitesize,forwhichOhba’sconjecturehasbeenverifiedarenothingmorethanthegraphsKt+3,2*(k-t-1),1*tbyEnotomoetal.,andKt+2,3,2*(k-t-2),1*tfort≤4byShenetal..Inthispaper,usingtheconceptoff-choosable(orL0-size-choosable)ofgraphs,weshowthatOhba’sconjectureisalsotrueforthegraphsKt+2,3,2*(k-t-2),1*twhent≥5.Thus,Ohba’sconjectureistrueforgraphsKt+2,3,2*(k-t-2),1*tforallintegerst≥1.
简介:相对增益阵列(RGA)大多数应用的矩阵阶数都是较小的(n=2,3或4).我们从矩阵方程Φ(A)=1/2J2的实数解出发,应用矩阵方程Φ(A)=1/nJn的实数解在G-等价下的不变性和实数解的分块构造法,研究了Φ(A)=1/4J4的实数解的一些问题.
简介:UsingthemethodofGirsanovtransformation,weestablishtheTalagrand'sT2-inequalityfordiffusiononthepathspaceC([0,N],R^d)withrespecttoauniformmetric,withtheconstantindependentofN.ThisimprovestheknownresultsfortheL2-metric.
简介:Inthispaper,weobtainaresultthatimprovestheresultsofGovilandNwaeze,QaziandtheclassicalresultofRivlin.
简介:本文用临界点理论中的能量最小原理得到了一类具(q(t),P(t))-Laplacian项的二阶非自治系统存在周期解的充分条件.
简介:Weintroducethecategoryoft-foldmoduleswhichisafullsubcategoryofgradedmodulesoveragradedalgebra.Weshowthatthissubcategoryandhencethesubcategoryoft-Koszulmodulesarebothclosedunderextensionsandcokernelsofmonomorphisms.Westudytheone-pointextensionalgebras,andanecessaryandsufficientconditionforsuchanalgebratobet-Koszulisgiven.Wealsoconsidertheconditionssuchthatthecategoryoft-Koszulmodulesandthecategoryofquadraticmodulescoincide.
简介:给出了n阶带形状参数的三角多项式T-Bézier基函数.由带形状参数的三角多项式T-Bézier基组成的带形状参数的T-Bézier曲线,可通过改变形状参数的取值而调整曲线形状,随着形状参数的增加,带形状参数的T-Bézier曲线将接近于控制多边形,并且可以精确表示圆、螺旋线等曲线.阶数的升高,形状参数的取值范围将扩大.
简介:Letp(z)=a_0+a_1z+a_2z~2+a_3z~3+···+a_nz~nbeapolynomialofdegreen.Rivlin[12]provedthatifp(z)≠0intheunitdisk,thenfor0
简介:论证了零级υ值代数体函数w(z)在满足某些条件下T方向的存在性,同时给出了最大型Borel方向与T方向之间的关系.