Before revision:  We demonstrate a  tradeoff between the number of hidden states and the number of hidden timesteps needed to implement any given f using a CTMC, analogous to space / time tradeoffs in theoretical computer science  .
After revision:  We demonstrate a tradeoff between the number of hidden states and the number of hidden timesteps needed to implement any given f using a CTMC, analogous to space / time tradeoffs in theoretical computer science . They can also be viewed as a type of resource theory, applying to master equation models of physical systems rather than quantum computation .