3 citations · 9 across the 12 of their papers we have counts for
17 papers
A proof of the Borel completeness of torsion free abelian groups
Michael C. Laskowski, Douglas S. Ulrich
A proof of the Borel completeness of torsion free abelian groups is presented. This proof differs considerably from the approach of Paolini-Shelah.
Characterizing the existence of a Borel complete expansion
Michael C. Laskowski, Douglas S. Ulrich
We develop general machinery to cast the class of potential canonical Scott sentences of an infinitary sentence as a class of structures in a related language. From this, we sh…
Most(?) theories have Borel complete reducts
Michael C. Laskowski, Douglas S. Ulrich
We prove that many seemingly simple theories have Borel complete reducts. Specifically, if a countable theory has uncountably many complete 1-types, then it has a Borel complete re…
Pseudosaturation and the Interpretability Orders
Douglas Ulrich
We streamline treatments of the interpretability orders of Shelah, the key new notion being that of pseudosaturation. Extending work of Malliaris and Shelah,…
Cardinal Characteristics of Models of Set Theory
Douglas Ulrich
We continue our investigation =of Shelah's interpretability orders as well as the new orders . In particular, we give streamlined pr…
Amalgamation and Keisler's Order
Danielle Ulrich
Malliaris and Shelah famously proved that Keisler's order has infinitely many classes. In more detail, for each , let be the theory o…