Julia F. Knight
(University of Notre Dame)
Classification of Countable Structures and the Effective Borel Hierarchy

Let K be a class of structures for a fixed computable language, with universe ω, or a subset, and closed under isomorphism. Classifying the members of K, up to isomorphism, involves understanding and describing the different isomorphism types. We may try to study the isomorphism relation on K directly, or we may use Turing computable embeddings to reduce the classification problem of one class to that of another class. I will describe some new results in this program.