List colorings of edge-critical graphs
Conjecture Suppose that is a -edge-critical graph. Suppose that for each edge of , there is a list of colors. Then is -edge-colorable unless all lists are equal to each other.
(Reproduced from [M].)
A graph is said to be -edge-critical if it is not -edge-colorable but every edge-deleted subgraph is -edge-colorable. (Here is the maximum degree of .)
Bibliography
*[M] B. Mohar, Problem of the Month
* indicates original appearance(s) of problem.