  Comprehending complex systems by simplifying and highlighting important
dynamical patterns requires modeling and mapping higher-order network flows.
However, complex systems come in many forms and demand a range of
representations, including memory and multilayer networks, which in turn call
for versatile community-detection algorithms to reveal important modular
regularities in the flows. Here we show that various forms of higher-order
network flows can be represented in a unified way with networks that
distinguish physical nodes for representing a~complex system's objects from
state nodes for describing flows between the objects. Moreover, these so-called
sparse memory networks allow the information-theoretic community detection
method known as the map equation to identify overlapping and nested flow
modules in data from a range of~different higher-order interactions such as
multistep, multi-source, and temporal data. We derive the map equation applied
to sparse memory networks and describe its search algorithm Infomap, which can
exploit the flexibility of sparse memory networks. Together they provide a
general solution to reveal overlapping modular patterns in higher-order flows
through complex systems.
