The Exsitence And Number Of Limit Cycles In Allelic Migration-selection Models

In this thesis,we mainly consider two-dimensional,three-dimensional and four-dimensional allelic migration-selection models.In the two-dimensional allelic migrationselection models,we discuss the change trend of allele relative frequency in the generalized logistic model.In the three-dimensional and four-dimensional allelic migration-selection models,according to the Liapunov stability theorem,Hopf bifurcation theory and center manifold theorem,we calculate the Liapunov constant and obtain the existence and number of limit cycles.