High Quality Content by WIKIPEDIA articles! In type theory, Hindley–Milner (HM) (also known as Damas–Milner or Damas–Hindley–Milner) is a classical type inference method with parametric polymorphism for the lambda calculus, first described by J. Roger Hindley and later rediscovered by Robin Milner. Luis Damas contributed a close formal analysis and proof of the method in his PhD thesis.