I was wondering whether the following two statement are true and why:
- For any two forcing notions $\mathbb{P,Q}$, if $\ \Vdash_\mathbb{Q} ``$There is a $\check{\mathbb{P}}$-generic filter over $\dot{V}"$, where $\dot{V}$ is the canonical name for the ground model, then there is a complete embedding from $\mathbb{P}$ to $\mathbb{Q}$.
- For any two forcing notions $\mathbb{P,Q}$, if there is a complete embedding from $\mathbb{P\times P}$ to $\mathbb{P\times Q}$ then there is also one from $\mathbb{P}$ to $\mathbb{Q}$
Both statements seems relatively simple, but nonetheless I'm having difficulties in proving them (or disproving).
Any hint or reference is much appreciated.
These are completely false.
For the first one, let $\Bbb Q$ be the Cohen forcing, and let $\Bbb P$ be the lottery sum of uncountably many Cohen forcings. Namely, $\Bbb P$ is an iteration of "pick a countable ordinal, then add a Cohen real".
In the second case, let $\Bbb P$ be the collapse $\operatorname{Col}(\omega,\omega_1)$, and let $\Bbb Q$ be the Cohen forcing.