Global attractivity in nonautonomous logistic equations with delay

A new criterion is proposed for the global asymptotic stability of the positive periodic solutions to the following delay logistic equation:u′(t)=u(t)[r(t)-a(t)u(t)-b(t)u(t-τ)].u′(t)=u(t)[r(t)-a(t)u(t)-b(t)u(t-τ)].This result is preceded by the stability property of the zero solution to the linear equationx′(t)=-a(t)x(t)-b(t)x(t-τ).x′(t)=-a(t)x(t)-b(t)x(t-τ).Previous investigations are confirmed and generalized.