DOI

We extend the recently introduced Luzin hierarchy of qcb0-spaces to all countable ordinals, obtaining in this way the hyperprojective hierarchy of qcb0-spaces. We generalize all main results for the former hierarchy to this larger hierarchy. In particular, we extend the Kleene-Kreisel continuous functionals of finite types to the continuous functionals of countable types and relate them to the new hierarchy. We show that the category of hyperprojective qcb0-spaces has much better closure properties than the category of projective qcb0-spaces. As a result, there are natural examples of spaces that are hyperprojective but not projective.
Original languageEnglish
Pages (from-to)1-17
Number of pages17
JournalComputability
Volume4
Issue number1
DOIs
StatePublished - 1 Jan 2015

    Research areas

  • Cartesian closed category, continuous functionals of countable types, Hyperprojective hierarchy, qcb0-space

ID: 126986033