Classification of Stable Surfaces with respect to Automatic Continuity

TL;DR

This paper classifies when the homeomorphism and mapping class groups of stable surfaces have the automatic continuity property, providing a general framework and extending results to Stone spaces, thus answering open questions.

Contribution

It offers a complete classification for stable surfaces and introduces a general framework for automatic continuity in groups of homeomorphisms.

Findings

Homeo() has automatic continuity for stable surfaces.

Classification of when mapping class groups have this property.

Homeo of stable second countable Stone spaces also has this property.

Abstract

We provide a complete classification of when the homeomorphism group of a stable surface, $\Sigma$, has the automatic continuity property: Any homomorphism from Homeo$(\Sigma)$ to a separable group is necessarily continuous. This result descends to a classification of when the mapping class group of $\Sigma$ has the automatic continuity property. Towards this classification, we provide a general framework for proving automatic continuity for groups of homeomorphisms. Applying this framework, we also show that the homeomorphism group of any stable second countable Stone space has the automatic continuity property. Under the presence of stability this answers two questions of Mann.