# Monotone recursive types and recursive data representations in Cedille

Guided by Tarksi's fixpoint theorem in order theory, we show how to derive monotone recursive types with constant-time roll and unroll operations within Cedille, an impredicative, constructive, and logically consistent pure type theory. As applications, we use monotone recursive types to generically derive two recursive representations of data in the lambda calculus, the Parigot and Scott encoding, together with constant-time destructors, a recursion scheme, and the standard induction principle.

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