Mixed finite element methods for nonlinear reaction-diffusion equations with interfaces

We develop mixed finite element methods for nonlinear reaction-diffusion equations with interfaces which have Robin-type interface conditions. We introduce the velocity of chemicals as new variables and reformulate the governing equations. The stability of semidiscrete solutions, existence and the a priori error estimates of fully discrete solutions are proved by fixed point theorem and continuous/discrete Gr$\ddot{o}$nwall inequalities. Numerical results illustrating our theoretical analysis are included.