2008 seminar talk: Definable cardianalities of boldface pointclasses

Talk held by Alessandro Andretta (Torino) at the KGRC seminar on 2008-06-26.


The question: "What is the size of a boldface pointclass?" is trivial under the Axiom of Choice, but becomes very interesting if we restrict ourselves to the realm of definable sets and maps. Assuming the Axiom of Determinacy a complete description of the cardinality of the boldface pointclasses is given, showing that the size of a pointclass is tightly related to its descriptive-set-theoretic comlexity.

This is joint work with G. Hjorth and I. Neeman.

Bottom menu

Kurt Gödel Research Center for Mathematical Logic. Währinger Straße 25, 1090 Wien, Austria. Phone +43-1-4277-50501. Last updated: 2010-12-16, 04:37.