  Bandyapadhyay et al. introduced the generalized minimum-membership geometric
set cover (GMMGSC) problem [SoCG, 2023], which is defined as follows. We are
given two sets $P$ and $P'$ of points in $\mathbb{R}^{2}$, $n=\max(|P|, |P'|)$,
and a set $\mathcal{S}$ of $m$ axis-parallel unit squares. The goal is to find
a subset $\mathcal{S}^{*}\subseteq \mathcal{S}$ that covers all the points in
$P$ while minimizing $\mathsf{memb}(P', \mathcal{S}^{*})$, where
$\mathsf{memb}(P', \mathcal{S}^{*})=\max_{p\in P'}|\{s\in \mathcal{S}^{*}: p\in
s\}|$. We study GMMGSC problem and give a $16$-approximation algorithm that
runs in $O(m^2\log m + m^2n)$ time. Our result is a significant improvement to
the $144$-approximation given by Bandyapadhyay et al. that runs in
$\tilde{O}(nm)$ time.
  GMMGSC problem is a generalization of another well-studied problem called
Minimum Ply Geometric Set Cover (MPGSC), in which the goal is to minimize the
ply of $\mathcal{S}^{*}$, where the ply is the maximum cardinality of a subset
of the unit squares that have a non-empty intersection. The best-known result
for the MPGSC problem is an $8$-approximation algorithm by Durocher et al. that
runs in $O(n + m^{8}k^{4}\log k + m^{8}\log m\log k)$ time, where $k$ is the
optimal ply value [WALCOM, 2023].
