Summary: Fixed Points of Type Constructors
and Primitive Recursion
Andreas Abel
joint work with Ralph Matthes
CSL'04
Karpacz, Karkonoski National Park, Poland
September 21, 2004
Work supported by: GKLI (DFG), TYPES & APPSEM-II (EU), CoVer (SSF)
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Regular Data Types
· Regular data types in Haskell:
data Nat = Zero | Succ Nat
data List a = Nil | Cons a (List a)
· Least fixed points of type transformers of kind :
NatF :
NatF := X. 1 + X
Nat :
Nat := µ NatF
· Works also for List, since parameter a can be abstracted.
List :

Source: Abel, Andreas - Theoretische Informatik, Ludwig-Maximilians-Universität München

Collections: Computer Technologies and Information Sciences