One approach to constrained reinforcement learning encodes safety guarantees in training by adapting TRPO's performance-improvement bound to cost constraints.

“At kind of all of these guarantees you try to encode into uh kind of into the training process itself. And that different ways of doing that. So one of the f very earliest was uh basically they went and looked at T_R_P_O_ and said well we have this like performance improvement bound, we can do exactly the same thing for costs.”