The Conservation Theorem revisited

@inproceedings{Groote1993TheCT,
  title={The Conservation Theorem revisited},
  author={Philippe de Groote},
  booktitle={TLCA},
  year={1993}
}
This paper describes a method of proving strong normalization based on an extension of the conservation theorem. We introduce a structural notion of reduction that we call βS , and we prove that any λ-term that has a βIβS-normal form is strongly β-normalizable. We show how to use this result to prove the strong normalization of different typed λ-calculi.