Size of edge-critical uniquely 3-colorable planar graphs

Zepeng Li, Enqiang Zhu, Zehui Shao +1

A graph $G$ is \emph{uniquely k-colorable} if the chromatic number of $G$ is $k$ and $G$ has only one $k$-coloring up to permutation of the colors. A uniquely $k$-colorable graph $…