A Property of the Intrinsic Mutual Information

Matthias Christandl and Renato Renner and Stefan Wolf


The so-called intrinsic mutual information is an important measure in
the context of information-theoretic secret-key agreement. We prove a
property of this information measure which, in particular, strongly
simplifies its computation. More generally, our result is useful for
analyzing the correlation of two random variables conditioned on a
third one.