1992/09/03 by Menachem Kojman, Saharon Shelah, Kojman, Menachem +1 · 1 citation
Mathematics · Computer Science · #Advanced Topology and Set Theory #Mathematical and Theoretical Analysis #Computability, Logic, AI Algorithms
paper · pdf · doi:10.48550/arxiv.math/9209201
Our theme is that not every interesting question in set theory is independent of ZFC. We give an example of a first order theory T with countable D(T) which cannot have a universal model at ℵ1 without CH; we prove in ZFC a covering theorem from the hypothesis of the existence of a universal model for some theory; and we prove --- again in ZFC --- that for a large class of cardinals there is no universal linear order (e.g. in every ℵ1