Special Session 89: 

Perspectives in nonlinear diffusion equations as asymptotic limits of Cahn--Hilliard systems

Takeshi Fukao
Kyoto University of Education
Japan
Co-Author(s):    Taishi Motoda
Abstract:
In this talk, recent advances in nonlinear diffusion equations as asymptotic limits of Cahn--Hilliard systems is treated. The weak formulation of the Stefan problem, the porous media equation, the fast diffusion equation, the weak formulation of Hele-Shaw equation and many other nonlinear diffusion equations of the form $$\frac{\partial u}{\partial t}-\Delta \beta (u) = g$$ are target problems. In Fukao (2016) and Colli--Fukao (2016), an idea of asymptotic limits of Cahn--Hilliard system is introduced for the characterization of the solution. More precisely, as the level of approximation the term of nonlinear diffusion $\beta (u)$ is treated as a monotone term in the Cahn--Hilliard system. $$\frac{\partial u}{\partial t}-\Delta \mu = 0, \quad \mu =-\varepsilon \Delta u + \beta (u) + \pi_\varepsilon (u)-f.$$ This approach has an advantage to improve the growth condition of $\hat{\beta }$, the primitive of nonlinear term $\beta$. The problem is considered under the Robin type boundary condition in this talk. This study is based on the joint work with Taishi Motoda, Kyoto University of Education.