简介:<正>Foranyintegersa1,a2,a3,a4andcwitha1a2a3a40(modp),thispapershowsthatthereexistsasolutionX=(x1,x2,x3,x4)∈Z4ofthecongruencea1x12+a2x22+a3x32+a4x42≡c(modp)suchthat‖X‖=max{|x1|,|x2|,|x3|,|x4|}《p1/2logp.
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.