1 citations · 2 across the 6 of their papers we have counts for
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The conjugacy relation on unitary representations
Greg Hjorth, Asger Tornquist
We show that the unitary conjugacy relation for unitary representations of a second countable locally compact group on a separable Hilbert space is a Borel equivalence relation.
Independently Axiomatizable L_{omega_1,omega} Theories
Greg Hjorth, Ioannis Souldatos
In partial answer to a question posed by Arnie Miller (http://www.math.wisc.edu/~miller/res/problem.pdf) and X. Caicedo, we obtain sufficient conditions for an L_{omega_1,omega} th…
Vaught's conjecture on analytic sets
Greg Hjorth
This paper obtains an algebraic characterization of the Polish groups that satisfy Vaught's conjecture on sets.
A universal Polish G-space
Greg Hjorth
If G is a Polish group, then there is a Polish G-space X which is universal among Polish G-spaces with respect to continuous G-embeddings.
Orbit cardinalities
G. Hjorth
This paper considers "definable cardinalities" arising from Polish group actions. The first part of the paper answers a question of Becker-Kechris by showing that under suitable de…
Sharper changes in topologies
Greg Hjorth
Becker and Kechris showed that if a Polish group G acts continuously on a Polish space X, then for any invariant Borel set B we can change the topology on X so that B becomes open,…
The Cardinality of the second uniform indiscernible
Greg Hjorth
When the second uniform indiscernible is , the Martin-Solovay tree only constructs countably many reals; this resolves a number of open questions in descriptive set the…