  Delay mass-action systems provide a model of chemical kinetics when past
states influence the current dynamics. In this work, we provide a
graph-theoretic condition for delay stability, i.e., linear stability
independent of both rate constants and delay parameters. In particular, the
result applies when the system has no delay, implying asymptotic stability for
the ODE system. The graph-theoretic condition is about cycles in the directed
species-reaction graph of the network, which encodes how different species in
the system interact.
