The list color function of a graph
is the minimum number of proper
colorings permitted by a list assignment that gives each graph
vertex exactly
available colors. If
counts the proper colorings selecting the color
of each graph vertex from its list
, then
Giving every graph vertex the same list shows that ,
where
is the chromatic polynomial. The least
for which
is the choice number.
For every graph , the list color function equals its chromatic
polynomial for all sufficiently large
. Equality for every positive
integer
is enumerative chromatic choosability
(Allred and Mudrock 2026). For an
-vertex tree,
.
Both counting functions multiply over connected components.