8 papers · 1 filter
General real-valued theories with the Schröder-Bernstein property are stable
Alexander Berenstein, Nicolás Cuervo Ovalle, Isaac Goldbring
We show that every general theory à la Keisler with the Schröder-Bernstein property is stable. This generalizes the corresponding result from classical logic due to John Goodrick.…
The Schröder-Bernstein property for operators on Hilbert spaces
Nicolás Cuervo Ovalle, Isaac Goldbring, Netanel Levi
We establish that the complete theory of a Hilbert space equipped with a normal operator has the Schröder-Bernstein property. This answers a question of Argoty, Berenstein, and th…
Model theory of Hilbert spaces expanded by normal operators
Alexander Berenstein, Nicolás Cuervo Ovalle, Isaac Goldbring
We study expansions of Hilbert spaces with a bounded normal operator . We axiomatize this theory in a natural language and identify all of its completions. We prove the definabi…
Existentially closed measure-preserving actions of approximately treeable groups
Isaac Goldbring, Brandon Seward, Robin Tucker-Drob
Given a countable group , letting denote the class of {\pmp} actions of , we study the question of when the model companion of exists. Ber…
Computable presentations of randomizations
Nicolás Cuervo Ovalle, Isaac Goldbring
We initiate the effective metric structure theory of Keisler randomizations. We show that a classical countable structure has a decidable presentation if and only if…
Computable -theory for -algebras: UHF algebras
Christopher Eagle, Isaac Goldbring, Timothy McNicholl +1
We initiate the study of the effective content of -theory for -algebras. We prove that there are computable functors which associate, to a computably enumerable pr…