  This paper studies the fundamental limits of content delivery in a
cache-aided broadcast network for correlated content generated by a discrete
memoryless source with arbitrary joint distribution. Each receiver is equipped
with a cache of equal capacity, and the requested files are delivered over a
shared error-free broadcast link. A class of achievable correlation-aware
schemes based on a two-step source coding approach is proposed. Library files
are first compressed, and then cached and delivered using a combination of
correlation-unaware multiple-request cache-aided coded multicast schemes. The
first step uses Gray-Wyner source coding to represent the library via private
descriptions and descriptions that are common to more than one file. The second
step then becomes a multiple-request caching problem, where the demand
structure is dictated by the configuration of the compressed library, and it is
interesting in its own right. The performance of the proposed two-step scheme
is evaluated by comparing its achievable rate with a lower bound on the optimal
peak and average rate-memory tradeoffs in a two-file multiple-receiver network,
and in a three-file two-receiver network. Specifically, in a network with two
files and two receivers, the achievable rate matches the lower bound for a
significant memory regime and it is within half of the conditional entropy of
files for all other memory values. In the three-file two-receiver network, the
two-step strategy achieves the lower bound for large cache capacities, and it
is within half of the joint entropy of two of the sources conditioned on the
third one for all other cache sizes.
