linear partial differential equations related to size-structured population models with diffusion Nobuyuki Kato PII: S0022-247X(15)01150-6 DOI: http://dx.Please cite this article in press as: N. Kato, Abstract linear partial differential equations related to size-structured population models with diffusion, J. Math. Anal. Appl. (2016), http://dx.Abstract linear partial differential equations related to size-structured population models with diffusion
AbstractWe study abstract linear partial differential equations in Banach spaces and/or Banach lattices related to size-structured population models with spatial diffusion and their dual problems. We introduce mild solutions through semigroup theory and characteristic method and investigate differentiability of mild solutions. Existence of a unique mild solution is shown. Also, a comparison result is obtained as well as the boundedness of mild solutions is investigated in the Banach lattice setting. Furthermore, we consider the dual problems, and then we introduce weak solutions and establish their uniqueness.Keywords: Size-structured populations with diffusion, characteristic curves, semigroup, mild solutions, dual problems, weak solutions 2010 MSC: 35Q92, 47D06, 92D25
Size-structured population models with diffusionLet us consider a biological population living in a habitat Ω ⊂ R n with smooth boundary ∂Ω. Let p(s, t, x) be the population density of size s ∈ [0, s † ] at time t ∈ [0, T ] in position x ∈ Ω, where s † ∈ (0, ∞) is the finite maximum size, T ∈ (0, ∞) is a given time. As usual, the spatial diffusion is represented by Laplacian kΔ with diffusion coefficient k > 0 and we assume the individuals do not move outside of Ω through the boundary ∂Ω. Denote by g(s, t) the growth rate of the individuals of size s and time t. Let μ(s, t, x) and β(s, t, x) be the mortality and reproduction rates, respectively, of size s