Forcing Diamond and Applications to Iterability
Heike Mildenberger, Saharon Shelah · arXiv (Cornell University) · 2025
We show that higher Sacks forcing at a regular limit cardinal and club Miller forcing at an uncountable regular cardinal both add a diamond sequence. We answer the longstanding question, whether $κ= κ^{<κ} \geq\aleph_1$ implies that $κ$-supported iterations of $κ$-Sacks forcing do not collapse $κ^+$ and are $κ$-proper in the affirmative. The results pertain to other higher tree forcings.