An Abstract Böhm-normalization

We study normalization by neededness with respect to ‘infinite results’, such as Böhm-trees, in an abstract framework of Stable Deterministic Residual Structures. We formalize the concept of ‘infinite results’ for finite terms as suitable sets of infinite reductions, and prove an abstract infinitary normalization theorem with respect to such sets. We also give a sufficient and necessary condition for existence of minimal normalizing reductions