Skip to main content
4 of 4
deleted 819 characters in body; edited tags; edited title
Sam Roberts
  • 1.2k
  • 1
  • 7
  • 15

Elementary embeddings and replacement

Let $\alpha\not= 0$ be such that for every $\beta<\alpha$ there is $\beta<\gamma<\alpha$, where $V_\gamma$ is an elementary substructure of $V_\alpha$. In other words, $V_\alpha$ is a limit of its $V_\beta$ elementary substructures. Then it is a simple result that $V_\alpha$ models replacement.

My question: Let $\alpha\not= 0$ be such that for every $\beta<\alpha$ there is $\beta<\gamma<\alpha$ and an elementary embedding from $V_\gamma$ to $V_\alpha$. Does it follow that $V_\alpha$ models replacement?

Sam Roberts
  • 1.2k
  • 1
  • 7
  • 15