The formal language L^λ_ar of acyclic recursion and its type-theory was introduced by Moschovakis between 2003 and 2006 for applications to computational semantics of human languages. Independently, implementations of large-scale grammars within the HPSG framework have been using semantic representations casted in the language of Minimal Recursion Semantics (MRS). While lacking strict formalization, MRS represents successfully ambiguous quantifier scoping. In this paper, we introduce the basic definitions of MRS by reflecting on possibilities for formalization of MRS with a version of the language L^λ_ar.