Abstract :
In this paper we consider the class C T of all dissipative 3-dimensional
T-periodic Kolmogorov competitive and cyclic systems such that the trivial solution
is a source, and we prove that “almost” every such system possesses a coexistence
state. More precisely, we characterize an open and dense subset U of C T , with
respect to the topology of the uniform convergence in compact sets, such that each
member of U has a coexistence state.