Graph recoloring is the transformation of one proper vertex coloring of a graph into another by changing the color
of one graph vertex at a time while keeping every
intermediate coloring proper. The -reconfiguration graph
has the proper vertex
colorings of
using
available colors as vertices, with two adjacent iff they differ at exactly one graph
vertex. A graph
is recolorable if
is connected for every
, where
is the chromatic number.
Huang et al. (2026) proved that every clique blowup of the cycle graph
is recolorable iff
is 3, 4, 5, or 7. Here a clique blowup replaces each graph
vertex by a nonempty clique and joins two replacement
cliques completely precisely when their original vertices
were adjacent. This differs from the independent
vertex set replacement used in a graph blow-up.