“Computable Model Theory of Torsion-Free Abelian Groups”

Sam Eisenstat, Department of Pure Mathematics, University of Waterloo

Countable torsion-free abelian groups are very complicated objects in general. We focus on groups that are direct sums of subgroups of $\mathbb{Q}$ and investigate their computability-theoretic properties. We look at degree spectra, categoricity, complexity of presentations, and complexity of the index and isomorphism problems. $\Sigma_{7}$ shows up!

But first, we let Mohammad finish his lemma from last time.

MC 5046