Special Session 15: 

Partial energy-dissipation and smoothing effect for constrained Allen-Cahn equations

Goro Akagi
Tohoku University
Japan
Co-Author(s):    Goro Akagi
Abstract:
In this talk, we shall discuss energy-dissipation phenomena and smoothing effect of solutions for an Allen-Cahn equation with nondecreasing constraint. More precisely, we shall treat the Cauchy-Dirichlet problem for the equation $$ u_t = \Big( \Delta u - W`(u) \Big)_+, $$ where $W(\cdot)$ is a double-well potential and $(\cdot)_+$ is the positive-part function. Hence solutions are constrained to be nondecreasing. Such a constraint prevents emergence of the energy-dissipation and smoothing effect, which are completely realized for classical Allen-Cahn equation. As a result, one can prove non-existence of global attractor in any $L^p$-spaces (and hence, in any Sobolev spaces). On the other hand, this equation still involves a gradient structure, and hence, energy-dissipation and smoothing effect emerge in an incomplete way. Main purpose of this talk is to explain how to extract such an incomplete emergence of energy-dissipation and smoothing effect for evolution equations with nondecreasing constraint from a functional analytic point of view. This talk is based on a joint work with M. Efendiev (M\"unchen).