本文通过无穷小母元的谱性质讨论人口半群的性质,证明了:存在 t_0>0,当 t>t_0时,人口半群{T(t)|t≥0)}是可微的.在一个安定的社会中,人口密度函数 P(r,t)满足偏微分方程...

In this paper we discuss the property of the population semigroup in terms of propertiesof its infinitesimal generator.we prove that there exists a t_0>0 such that the populationsemigroup {T(t)|>0} is differentiable for t>t_0.