4 papers
Scott-Karp analysis without sentences
Andreas Brunner, Charles Morgan, Darllan Concieção Pinto
Scott and Karp gave an analysis which provides a level-by-level equivalence between global similarity between two structures and local commonality in terms of sharing particular in…
Some contributions to presheaf model theory, II -- back and forth
Andreas Brunner, Charles Morgan, Darllan Conceição Pinto
We discuss the back and forth technique in the context of presheaf model theory. The essence of the back and forth technique lies in showing the relationship between various hierar…
Some contributions to presheaf model theory
Andreas Brunner, Charles Morgan, Darllan Conceição Pinto
This paper makes contributions to ``pure'' sheaf model theory, the part of model theory in which the models are sheaves over a complete Heyting algebra. We start by outlining the t…
On forcing axioms and weakenings of the Axiom of Choice
Diego Lima Bomfim, Charles Morgan, Samuel Gomes da Silva
We prove forcing axiom equivalents of two families of weakenings of the axiom of choice: a trichotomy principle for cardinals isolated by Lévy, , and ${\rm…