[FOM] Combinatorial objects with no computable instances

Andrej Bauer andrej.bauer at andrej.com
Tue Jan 31 18:02:33 EST 2012

> Was Specker's result indeed the first of this kind?

Kleene predated this with his computable unbounded tree whose every
path is non-computable:

S.C. Kleene. Recursive functions and intuitionistic mathematics.
In L.M. Graves, E. Hille, P.A. Smith, and O. Zariski, editors,
Proceedings of the International Congress of Mathemaiticans,
August 1950. Cambridge, Mass., pages 679–685, 1952

With kind regards,


More information about the FOM mailing list