  Caro, Davila, and Pepper (arXiv:1909.09093) recently proved $\delta(G)
\alpha(G)\leq \Delta(G) \mu(G)$ for every graph $G$ with minimum degree
$\delta(G)$, maximum degree $\Delta(G)$, independence number $\alpha(G)$, and
matching number $\mu(G)$. Answering some problems they posed, we characterize
the extremal graphs for $\delta(G)<\Delta(G)$ as well as for
$\delta(G)=\Delta(G)=3$.
