ON THE SEMIGROUP FOR AGE-DEPENDENT POPULATION-DYNAMICS WITH SPATIAL DIFFUSION

We continue a population model with age dependence and spatial diffusi on in the semigroup framework, in which the assumptions of our previou s paper [Manuscripta Math. 66 (1990), 161-180] that birth and death ra tes are independent of spatial variables are removed. The infinitesima l generator is identified and its spectrum studied, and accordingly, b y using a positive semigroup theory, we determine its dominant eigenva lue and hence the asymptotic expression is obtained. (C) 1994 Academic Press, Inc.