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    N^N^N does not satisfy Normann's condition

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    We prove that the Kleene-Kreisel space N^N^N does not satisfy Normann's condition. A topological space XX is said to fulfil Normann's condition, if every functionally closed subset of XX is an intersection of clopen sets. The investigation of this property is motivated by its strong relationship to a problem in Computable Analysis. D. Normann has proved that in order to establish non-coincidence of the extensional hierarchy and the intensional hierarchy of functionals over the reals it is enough to show that N^N^N fails the above condition.Comment: 10 page
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