Define the term "reward" in reinforcement learning.
In reinforcement learning (RL), a reward is a scalar feedback signal provided by the environment to the agent after it takes an action in a particular state. The reward signal indicates the immediate desirability or undesirability of the action taken by the agent in the current state.
Key characteristics of rewards in RL include :
* Scalar Value
* Immediate Feedback
* Objective Function
* Incentive Structure
* Stochasticity
* Sparse or Dense.
