In a lecture in Kazan (1977), Goncharov dubbed a number of problems regarding the
classification of computable members of various classes of structures. Some of the problems …

Defining the degree of categoricity of a computable structure M to be the least degree d for
which M is d-computably categorical, we investigate which Turing degrees can be realized …

In mathematics, we know there are some concepts-objects, constructions, structures, proofs-
that are more complex and difficult to describe than others. Computable structure theory …

3. Theories, types, models, and diagrams. 138 4. Small theories and their models. 144 5.
Effective categoricity. 148 6. Automorphisms of effective structures. 156 7. Degree spectra of …

Fried and Kollár constructed a fully faithful functor from the category of graphs to the
category of fields. We give a new construction of such a functor and use it to resolve a …

Our main result is the equivalence of two notions of reducibility between structures. One is a
syntactical notion which is an effective version of interpretability as in model theory, and the …

We investigate the problem of punctual (fully primitive recursive) presentability of algebraic
structures up to primitive recursive and computable isomorphism. We show that for mono …

A Polish space is not always homeomorphic to a computably presented Polish space. In this
article, we examine degrees of non-computability of presenting homeomorphic copies of …

Comparing Classes of Finite Structures Page 1 Algebra and Logic, Vol. 43, No. 6, 2004
COMPARING CLASSES OF FINITE STRUCTURES W. Calvert, D. Cummins, JF Knight, and S …

§1. Introduction. The annual meeting of the Association for Symbolic Logic held in Urbana-Champaign,
June 2000, included a pane Page 1 The Bulletin of Symbolic Logic Volume7, Number2, June …