  Binary decision diagrams (BDDs) are widely used to mitigate the
state-explosion problem in model checking. A variation of BDDs are
Zero-suppressed Decision Diagrams (ZDDs) which omit variables that must be
false, instead of omitting variables that do not matter. We use ZDDs to
symbolically encode Kripke models used in Dynamic Epistemic Logic, a framework
to reason about knowledge and information dynamics in multi-agent systems. We
compare the memory usage of different ZDD variants for three well-known
examples from the literature: the Muddy Children, the Sum and Product puzzle
and the Dining Cryptographers. Our implementation is based on the existing
model checker SMCDEL and the CUDD library. Our results show that replacing BDDs
with the right variant of ZDDs can significantly reduce memory usage. This
suggests that ZDDs are a useful tool for model checking multi-agent systems.
