  This paper deals with a parabolic-elliptic chemotaxis system with nonlinear
diffusion. It was proved that there exists a solution of a Cahn-Hilliard system
as an approximation of a nonlinear diffusion equation by applying an abstract
theory by Colli-Visintin [Comm. Partial Differential Equations 15 (1990),
737-756] for a doubly nonlinear evolution inclusion with some bounded monotone
operator and subdifferential operator of a proper lower semicontinuous convex
function (cf. Colli-Fukao [J. Math. Anal. Appl. 429 (2015), 1190-1213]).
Moreover, Colli-Fukao [J. Differential Equations 260 (2016), 6930-6959]
established existence of solutions to the nonlinear diffusion equation by
passing to the limit in the Cahn-Hilliard equation. However, Cahn-Hilliard
approaches to chemotaxis systems with nonlinear diffusions seem not to be
studied yet. This paper will try to derive existence of solutions to a
parabolic-elliptic chemotaxis system with nonlinear diffusion by passing to the
limit in a Cahn-Hilliard type chemotaxis system.
