简介:SupposethatCisthecomplexplaneandkisanon-negativeinteger.DefinefunctionsNk-(x)=|x|kifkisevenandNk(x)=x|x|k-1ifkisodd.SomeapproximationpropertiesofNk-(x)’sisdiscussedandanewexampleofaTchebycheffsystemisgivenout.
简介:SomecharacterizationsoftheconditionalexpectationoperatorsonLebesgue-BochnerspacesL_p(μ,X)aregiven,where1≤p<∞,p≠2.AlsoanexampleisgiventoshowthatthecharacterizationsoftheconditionalexpectationoperatorsonL_p(μ,X)aredifferentfromthatonL_p(μ)_zFinally,arepresentationoftheconstant-preservingcontractiveprojectiononspacesL_p(μ,X)isgotwhen0
简介:Itiswellknownthateveryprimeidealminimaloveraz-idealisalsoaz-ideal.TheconverseisalsowellknowninC(X).ThuswheneverIisanidealinC(X),thenI~(1/2)isaz-idealifandonlyifIis,inwhichcaseI~(1/2)=I.Weshowthesamefactforz~o-idealsandthenitturnsoutthatthesumofaprimaryidealandaz-ideal(z~o-ideal)inC(X)whicharenotinachainisaprimez-ideal(z~o-ideal).Wealsoshowthateverydecomposablez-ideal(z~o-ideal)inC(X)istheintersectionofafinitenumberofprimez-ideals(z~o-ideal).Somecounter-examplesingeneralringsandsomecharacterizationsforthelargest(smallest)z-idealandz~o-idealcontainedin(containing)anidealaregiven.
简介:最近,Brutman和Passow认为Newman类型合理插值是to|x|由对称的节点的任意的集合导致了在[-1,1]并且给了近似错误的一般评价。由他们的方法,一个人能为一些特殊节点建立近似的准确顺序。在我们考虑插值节点是第二种类型的零个Chebyshev多项式并且在这种情况中证明那的特殊情况的现在的纸,近似的准确顺序是O(1/(nlnn))。
简介:<正>Foranoddfunctionf(x)definedonlyonafiniteinterval,thispaperdealswiththeexistenceofperiodicsolutionsandthenumberofsimpleperiodicsolutionsofthedifferentialdelayequation(DDE)(?)(t)=-f(x(t-1)).Byuseofthemethodofqualitativeanalysiscombinedwiththeconstructingofspecialsolutionsaseriesofinterestingresultsareobtainedontheseproblems.