An Alpha-Corecursion Principle for the Infinitary Lambda Calculus

  • Alexander Kurz
  • Daniela Petrişan
  • Paula Severi
  • Fer-Jan de Vries
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7399)


Gabbay and Pitts proved that lambda-terms up to alpha-equivalence constitute an initial algebra for a certain endofunctor on the category of nominal sets. We show that the terms of the infinitary lambda-calculus form the final coalgebra for the same functor. This allows us to give a corecursion principle for alpha-equivalence classes of finite and infinite terms. As an application, we give corecursive definitions of substitution and of infinite normal forms (Böhm, Lévy-Longo and Berarducci trees).


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© IFIP International Federation for Information Processing 2012

Authors and Affiliations

  • Alexander Kurz
    • 1
  • Daniela Petrişan
    • 1
  • Paula Severi
    • 1
  • Fer-Jan de Vries
    • 1
  1. 1.Department of Computer ScienceUniversity of LeicesterUK

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