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The area of [[effective descriptive set theory]] combines the methods of descriptive set theory with those of [[generalized recursion theory]] (especially [[hyperarithmetical theory]]). In particular, it focuses on [[lightface]] analogues of hierarchies of classical descriptive set theory. Thus the [[hyperarithmetic hierarchy]] is studied instead of the Borel hierarchy, and the [[analytical hierarchy]] instead of the projective hierarchy. This research is related to weaker version of set theory such as [[Kripke-Platek set theory]] and [[second-order arithmetic]].
==Table==
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==See also==
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