Before revision: We extend the framework of a posteriori error estimation by preconditioning in [Li, Y., Zikatanov, L.: arXiv:2010.06774 (2020 )] and derive new a posteriori error estimates for Maxwell two-phase interface problems.
After revision: We extend the framework of a posteriori error estimation by preconditioning in [Li, Y., Zikatanov, L.: Computers \& Mathematics with Applications. )] and derive new a posteriori error estimates for Maxwell two-phase interface problems.