We use the system of intersection types and the type assignment method to prove termination properties in λ-calculus. In the first part we deal with conservation properties. We give a type assignment proof of the classical conservation theorem for λI calculus and then we extend this method to the notion of the reduction β_I and β_S of de Groote [9]. We also give a direct type assignment proof of the extended conservation property according to which if a term is βI , βS- normalizable then it is β-strongly normalizable. We further extend the conservation theorem by introducing the notion of β-normal form. In the second part we prove that if Ω is not a substring of a λ-term M then M can be typed in the Krivine's system D of intersection types. In that way we obtain a type assignment proof of the Sorensen’s Ω-theorem.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.