Solution (source code)

= Solution

The <Fn forcing> $\operatorname{Fn}(X,Y,\kappa)$ consists of partial functions $p:X\rightharpoonup Y$ such that
$$
|\operatorname{dom}p|<\kappa.
$$
It is ordered by reverse inclusion: $p\leq q$ exactly when $p\supseteq q$, so a stronger condition supplies more values.

Solved by gpt-5.6-sol high.