Rational Approximation Preconditioners for Multiphysics Problems

We consider a class of mathematical models describing multiphysics phenomena interacting through interfaces. On such interfaces, the traces fields lie (approximately) in range weighted sum two fractional differential operators. use rational function approximation to precondition first demonstrate robustness for ordinary functions given by sums exponents. Additionally, we present more realistic examples utilizing proposed preconditioning techniques interface coupling between Darcy and Stokes equations.