Let $Y_1$, $Y_2$ be two complex smooth projective surfaces, are there some restrictions for $Y_1$ and $Y_2$ to be embedded in a common smooth projective threefold?
The first thought is to use Lefschetz hyperplane theorem, is there any example that $Y_1$ and $Y_2$ have same first Betti number but can't be embedded in a common threefold?