This paper studies the general nonautonomous single-species Kolmogorov systems with delays. The sufficient conditions on the permanence of species and the existence of positive periodic solutions are established. As application of these results
the permanence and existence of positive periodic solutions for a series of special single-species growth systems with delays are obtained.
关键词
Keywords
references
Yuming Chen. Periodic solutions of a delayed periodic logistic equation[J]. Appl. Math. Letters, 2003,16:1 047-1 051.
K. Gopalsamy, M. R. S. Kulenovic and G. Ladas. Environmental periodicity and time delays in a food-limited population model[J]. J. Math. Anal. Appl., 1990,147:545-555.
K. Gopalsamy and B. S. Lalli. Oscillatory and asymptotic behavior of a multiplicative delay logistic equation[J]. Dy-nam. Stab. Syst. , 1992,7:35-42.
S. R. Grace, I. Gyori and B. S. Lalli. Necessary and sufficient conditions for the oscillations of a multiplicative delay logistic equation[J]. Quart. Appl. Math. , LⅢ,1995,69-79.
Y. Kuang. Delay Differential Equations with Applications in Population Dynamics[J]. Boston: Academic Press, 1993.
B. S. Lalli and B. G. Zhang. On a periodic populationmodel[J]. Quart. Appl. Math., LⅡ,1994, 35-42.
S. M. Lenhart and C. C. Travis. Global Stability of a biological model with time delay[J]. Proc. Amer. Math. Soc. , 1986,96:75-78.
Yongkun Li. The existence and global attractivity of periodic positive solutions for a class of delayed differential equa-tions[J]. Science in China (Series A), 1998,28:108-118.
Z. D. Teng and L. S. Chen. The positive periodic solutions of periodic Kolmogorov type systems with delays[J]. Acta Math. Appl. Sinica, 1999,22:456-464.
R. R. Vance and E. A. Coddington. A nonautonomous model of population growth[J]. J. Math. Biol. , 1989,27: 491-506.
B. G. Zhang and K. Gopalsamy. Global attractivity and oscillations in a periodic delay-logistic equation[J]. J. Math. Anal. Appl. , 1990,150:274-283.