一类时滞种群模型的周期正解.pdf

第15卷第1期 th 19991 68—71 P舾碰ed Pure纯粹and端毖M用u糕ematics POSITIVEPERIODICSOLUTIONSOFA MODELINPOPULATION。 HuangYongming of Education Mathematics，Yunnan (Department Cao Jinde Education (Adult College·Yunnan AbstractInthis ofsomenew and of using techniquestheory paper，by of existenceof solutionofaclass modelin degree．the positiveperiodic delayed pop- ulationofthefornl Ⅳ70)=Ⅳo)po)一∑a：nN(t—o)] j-1 areim- isstudied．Anewresultisobtained．andtheresultsrelatedtoreferences proved． words modelin Key delayed population；positiveperiodic degree· 1991MSC34C25，34K15 in Weconsider solutions ofthe aclassof model periodic problemfollowing delayed is ulation，that Logisticequation[1]； (1) ．Ⅳ’o)=Ⅳo)[60)一∑ajlnN(t—rj)3 j-1 withtheinitial condition： Ⅳ(s)；烈s)≥0,S∈[一r，o]。“o)0 (2) where continuousfunctionswith 60)ispositive periodic period positive constant，f—sup{t，J一1，2’．．·} estabilishtheexistenceconditionsof