1. Fully observable / Partially observable: If an agent’s sensors give it access to the complete state of the environment needed to choose an action, the environment is fully observable. Else, it is partial.
  2. Deterministic / Stochastic: An environment is deterministic if the next state of the environment is completely determined by the current state (PLUS THE RESULTS OF YOUR ACTIONS) of the environment and the action of the agent; In a stochastic environment, there are multiple, unpredictable RANDOM outcomes. Luck is a serious component.
  3. Episodic / Sequential: In an episodic environment, the agent’s experience is divided into atomic episodes. Each episode consists of the agent perceiving and then performing a single action. Subsequent episodes do not depend on what actions occurred in previous episodes - no memory. Choice of action in each episode depends only on the episode itself NOT THE PREVIOUS STATES. (E.g., classifying images.) In a sequential environment, the agent engages in a series of connected episodes. Current decision can affect future decisions. (E.g., chess and driving)
  4. Static / Dynamic: A static environment does not change while the agent is thinking (E.G. CHESS). The passage of time as an agent deliberates is irrelevant. The environment is semi- dynamic if the environment itself doesn’t change with the passage of time, but the agent's performance score does. DYMANIC when everything changes despite what actions are you currently doing.
  5. Discrete / Continuous: If the number of distinct percepts and actions is limited (FINITE), the environment is discrete, otherwise it is continuous.
  6. Single agent / Multi- agent: If the environment contains other intelligent agents, the agent needs to be concerned about strategic, game-theoretic aspects of the environment (for either cooperative or competitive - ADVERSIAL agents). Most engineering environments don’t have multi-agent properties, whereas most social and economic systems get their complexity from the interactions of (more or less) rational agents. CHESS is a multi- agent system (since the human is to be considered as an intelligent agent).

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