Distributive laws and Koszulness

Distributive law is a way to compose two algebraic structures, say ???? and ????, into a more complex algebraic structure ????. The aim of this paper is to understand distributive laws in terms of operads. The central result says that if the operads corresponding respectively to ???? and ???? are Koszul, then the operad corresponding to ???? is Koszul as well. An application to the cohomology of configuration spaces is given.