  The boxicity of a graph $G$ is the minimum non-negative integer $k$ such that
$G$ can be isomorphic to the intersection graph of a family of boxes in
Euclidean $k$-space, where a box in Euclidean $k$-space is the Cartesian
product of $k$ closed intervals on the real line. In this note, we define the
fractional boxicity of a graph as the optimum value of the linear relaxation of
a covering problem with respect to boxicity, which gives a lower bound for its
boxicity. We show that the fractional boxicity of a graph is at least the lower
bounds for boxicity given by Adiga et al. in 2014. We also present a natural
lower bound for fractional boxicity of graphs. Moreover we discuss and focus on
"accuracy" rather than "simplicity" of these lower bounds for boxicity as the
next step in Adiga's work.
