We study a coupled bulk-surface Allen-Cahn system with an affine linear
transmission condition, that is, the trace values of the bulk variable and the
values of the surface variable are connected via an affine relation, and this
serves to generalize the usual dynamic boundary conditions. We tackle the
problem of well-posedness via a penalization method using Robin boundary
conditions. In particular, for the relaxation problem, the strong
well-posedness and long-time behavior of solutions can be shown for more
general and possibly nonlinear relations. New difficulties arise since the
surface variable is no longer the trace of the bulk variable, and uniform
estimates in the relaxation parameter are scarce. Nevertheless, weak
convergence to the original problem can be shown. Using the approach of Colli
and Fukao (Math. Models Appl. Sci. 2015), we show strong existence to the
original problem with affine linear relations, and derive an error estimate
between solutions to the relaxed and original problems.Comment: 34 page
