2 problems

Let $P$ be a class forcing notion. A forcing notion is almost $\lambda_0,\lambda$-periodic if it is $\lambda_0,\lambda$-periodic in a set-generic extension of the universe, where…

Let $\eta$ be an ordinal and let $V$ be a model of $\mathsf{ZFC}$. An inner mantle is obtained by iterating the operation that sends a model to the intersection of its grounds. Fuc…