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Are there hyper-recurrent combinators?
The source page states the original problem together with its recorded qualifications and progress updates as follows.
A term in Combinatory Logic or -calculus is recurrent if whenever (this notion is due to M. Venturini-Zilli.) Let's call hyper-recurrent if is recurrent for all . (Equivalently, is hyper-recurrent if whenever .) Are there any hyper-recurrent combinators? (The problem comes up immediately when the Ershov-Visser theory [Statman, 1993] for is applied to . It is known that hyper-recurrent combinators don't exist for Combinatory Logic [Statman, 1993].)
