  Many complex systems demand manifold resources to be supplied from distinct
channels to function properly, i.e, water, gas, and electricity for a city.
Here, we study a model for viability of such systems demanding more than one
type of vital resources produced and distributed by resource nodes in multiplex
networks. We found a rich variety of behaviors such as discontinuity,
bistability, and hysteresis in the fraction of viable nodes with respect to the
density of networks and the fraction of resource nodes. Our result suggests
that viability in multiplex networks is not only exposed to the risk of abrupt
collapse but also suffers excessive complication in recovery.
