Positional strategies in long Ehrenfeucht-Fraiss\'e games
Abstract
We prove that it is relatively consistent with ZF + CH that there exist two models of cardinality 2 such that the second player has a winning strategy in the Ehrenfeucht-Fra\"iss\'e-game of length ω1 but there is no σ-closed back-and-forth set for the two models. If CH fails, no such pairs of models exist.
0
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.