  This paper studies the problem of upper bounding the number of independent
sets in a graph, expressed in terms of its degree distribution. For bipartite
regular graphs, Kahn (2001) established a tight upper bound using an
information-theoretic approach, and he also conjectured an upper bound for
general graphs. His conjectured bound was recently proved by Sah et al. (2019),
using different techniques not involving information theory. The main
contribution of this work is the extension of Kahn's information-theoretic
proof technique to handle irregular bipartite graphs. In particular, when the
bipartite graph is regular on one side, but it may be irregular in the other,
the extended entropy-based proof technique yields the same bound that was
conjectured by Kahn (2001) and proved by Sah et al. (2019).
