Orbit cardinals: On the effective cardinalities arising as quotient spaces of the form \(X/G\) where \(G\) acts on a Polish space \(X\)

DOI10.1007/BF02810686zbMath0945.03069MaRDI QIDQ1806265

Greg Hjorth

Publication date: 30 January 2000

Published in: Israel Journal of Mathematics (Search for Journal in Brave)

zbMATH Keywords

Polish spaceequivalence relationVaught's conjecturequotient spacemetric grouporbit structureeffective cardinalitycontinuous actions of Polish groupsgeneralization of Glimm-Effros dichotomy

Mathematics Subject Classification ID

Complete metric spaces (54E50) Descriptive set theory (03E15) Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) (54H05) Topological and differentiable algebraic systems (22A99)

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