Information-Geometric Equivalence of Transportation Polytopes

On the Hardness of Entropy Minimization and Related Problems

We investigate certain optimization problems for Shannon information measures, namely, minimization of joint and conditional entropies $H(X,Y)$, $H(X|Y)$, $H(Y|X)$, and maximization of mutual information $I(X;Y)$, over convex regions. When restricted to the so-called transportation polytopes (sets of distributions with fixed marginals), very simple proofs of NP-hardness are obtained for these problems because in that case they are all equivalent, and their connection to the well-known \textsc{Subset sum} and \textsc{Partition} problems is revealed. The computational intractability of the more …