  The paper aims to establish the Tur\'an inequalities, the Laguerre
inequalities (order $2$), and the determinantal inequalities (order $3$) for
$\Delta p(n)$ and $\Delta \bar{p}(n)$, where $\Delta f(n)$ is the first-order
forward difference of a sequence $f(n)$. The functions $p(n)$ and $\bar{p}(n)$
denote the partition function and overpartition function, respectively.
Conjectures for thresholds of Laguerre inequalities (order $m$) and positivity
of $m$-order determinants are proposed, extending to $\Delta^k p(n)$ and
$\Delta^k \bar{p}(n)$, with $1 \leq m \leq 11$ and $1 \leq k \leq 5$.
