3 papers
math.LO2024
Two-cardinal derived topologies, indescribability and Ramseyness
Brent Cody, Chris Lambie-Hanson, Jing Zhang
We introduce a natural two-cardinal version of Bagaria's sequence of derived topologies on ordinals. We prove that for our sequence of two-cardinal derived topologies, limit points…
math.LO2024
Squares, ultrafilters and forcing axioms
Chris Lambie-Hanson, Assaf Rinot, Jing Zhang
We study relationships between various set theoretic compactness principles, focusing on the interplay between the three families of combinatorial objects or principles mentioned i…
math.LO2024
The Second-order Version of Morley's Theorem on the Number of Countable Models does not Require Large Cardinals
Franklin D. Tall, Jing Zhang
The consistency of a second-order version of a theorem of Morley on the number of countable models was proved in arXiv:2107.07636 with the aid of large cardinals. We here dispense…