What is Reinforcement Learning?
Reinforcement Learning (RL) is a machine learning paradigm where an agent learns optimal behavior through trial and error, receiving rewards or penalties for actions taken in an environment.
WHY IT MATTERS
RL is how you teach systems to make sequential decisions. The agent takes actions in an environment, observes results, and receives a reward signal. Over many iterations, it learns which actions maximize cumulative reward — without being explicitly told what to do.
RL powers game-playing AI (AlphaGo, OpenAI Five), robotics, recommendation systems, and importantly, the RLHF process that aligns language models with human preferences.
For financial agents, RL is conceptually relevant: trading and portfolio management are sequential decision problems where you optimize cumulative returns. However, pure RL for live financial trading faces challenges with non-stationarity, sample efficiency, and catastrophic risk.