 (It's better to consider it in Ho(pro-SS); see Edwards) Using this inverse system of simplicial sets one may "sometimes" associate to a homotopy invariant in classical topology an inverse system of invariants in topos theory.The study of the pro-simplicial set associated to the étale topos of a scheme is called étale homotopy theory.In good cases (if the scheme is Noetherian and geometrically unibranch), this pro-simplicial set is pro-finite.