Metric Scott analysis
Abstract
We develop an analogue of the classical Scott analysis for metric structures and infinitary continuous logic. Among our results are the existence of Scott sentences for metric structures and a version of the Lopez-Escobar theorem. We also derive some descriptive set theoretic consequences: most notably, that isomorphism on a class of separable structures is a Borel equivalence relation iff their Scott rank is uniformly bounded below . Finally, we apply our methods to study the Gromov-Hausdorff distance between metric spaces and the Kadets distance between Banach spaces, showing that the set of spaces with distance to a fixed space is a Borel set.
Cite
@article{arxiv.1407.7102,
title = {Metric Scott analysis},
author = {Itai Ben Yaacov and Michal Doucha and Andre Nies and Todor Tsankov},
journal= {arXiv preprint arXiv:1407.7102},
year = {2017}
}
Comments
This preprint replaces and greatly expands our previous preprint "A Lopez-Escobar theorem for continuous logic" (without Doucha). Please only cite this current version. The previous material is contained in Section 6 in updated form. The paper is submitted as of July 2016. Key words: continuous logic, infinitary logic, Scott rank, Scott sentence, Lopez-Escobar theorem