  Quantum discord (QD) measures the fraction of the pairwise mutual information
that is locally inaccessible, in a multipartite system. Fundamental aspects
related to two important measures in quantum information theory the
Entanglement of Formation (EOF) and the conditional entropy, can be understood
in terms of the distribution of this form of Local Inaccessible Information
(LII). As such, the EOF for an arbitrarily mixed bipartite system AB can be
related to the gain or loss of LII due to the extra knowledge that a purifying
ancillary system E has on the pair AB. Similarly, a clear meaning of the
negativity of the conditional entropy for AB is given. We exemplify by showing
that these relations elucidate important and yet not well understood quantum
features, such as the bipartite entanglement sudden death and the distinction
between EOF and QD for quantifying quantum correlation. For that we introduce
the concept of LII flow which quantifies the LII shared in multipartite system
when a sequential local measurements are performed.
