Stationary Sets and Infinitary Logic

Let K0 be the class of structures , <, A , where A is disjoint from a club, and let K1 be the class of structures , <, A , where A contains a club. We prove that if = < is regular, then no sentence of L+ separates K0 and K1 . On the other hand, we prove that if =

• Type: Journal
• Year: 2000
• Where: JSYML
• Authors: Saharon Shelah, Jouko A. Väänänen
• Keywords: Club, Countable Well-ordered Structures, Fundamental Properties, JSYML 2000