2024/11/29 by Ivan Zelich, Zelich, Ivan
Computer Science · #Cellular Automata and Applications #Computability, Logic, AI Algorithms
paper · pdf · doi:10.48550/arxiv.2411.19944
We introduce the notion of indivisible sequences and show that to any indivisible sequence \S, Ψ: S → R\ we can associate faithfully flat ring maps R → R' that are not descendable. As a corollary, we obtain the first example of a faithfully flat ring map between ℵn-1-countable rings that has descendability exponent n, and indeed a faithfully flat ring map between ℵω-countable rings that is not descendable.