Math Problem Statement

A simple environment has 3 states which are encoded as integers 0 - 2, and 2 actions encoded as integers 0 and 1. Suppose that the environment is stochastic. The two tables below provide the transition probabilities for the two actions.

For example, if the agent is in state 2 and takes action 0, there is a 0.7 probability of transitioning to state 0, a 0.1 probability of transitioning to state 1, and a 0.2 probability of transitioning to state 2.

Transition Probabilities for Action 0

0 1 2 0 0.1 0.5 0.4 1 0.1 0.6 0.3 2 0.7 0.1 0.2

Transition Probabilities for Action 1

0 1 2 0 0.5 0.2 0.3 1 0.6 0.3 0.1 2 0.1 0.4 0.5

The agent starts in state 0 and generates an episode according to some policy. The states visited are provided by the list below.

states_visited = [0, 2, 1, 1, 2]

The actions taken by the agent are as follows:

actions_taken = [0, 1, 0, 0]

Use the tables above to determine the probability of each transition that occurred, given the actions that were taken. Then multiply these probabilities together to determine the probability of obtaining this sequence of states as a result of the actions taken.

Solution

To determine the probability of obtaining the given sequence of states as a result of the actions taken, we need to:

  1. Identify the probability of transitioning between each state given the action taken.
  2. Multiply these probabilities together to get the total probability of the sequence.

Let's proceed step by step.

Given Data:

  • States visited: [0, 2, 1, 1, 2]
  • Actions taken: [0, 1, 0, 0]

Transition Probabilities:

Action 0:

\text{State} & 0 & 1 & 2 \\ \hline 0 & 0.1 & 0.5 & 0.4 \\ 1 & 0.1 & 0.6 & 0.3 \\ 2 & 0.7 & 0.1 & 0.2 \\ \end{array}$$ #### Action 1: $$\begin{array}{c|c|c|c} \text{State} & 0 & 1 & 2 \\ \hline 0 & 0.5 & 0.2 & 0.3 \\ 1 & 0.6 & 0.3 & 0.1 \\ 2 & 0.1 & 0.4 & 0.5 \\ \end{array}$$ ### Steps: 1. **Transition from State 0 to State 2 with Action 0:** - Probability: $$P(0 \rightarrow 2 \mid \text{Action 0}) = 0.4$$ 2. **Transition from State 2 to State 1 with Action 1:** - Probability: $$P(2 \rightarrow 1 \mid \text{Action 1}) = 0.4$$ 3. **Transition from State 1 to State 1 with Action 0:** - Probability: $$P(1 \rightarrow 1 \mid \text{Action 0}) = 0.6$$ 4. **Transition from State 1 to State 2 with Action 0:** - Probability: $$P(1 \rightarrow 2 \mid \text{Action 0}) = 0.3$$ ### Total Probability: Now, multiply the probabilities of each transition together: $$\text{Total Probability} = 0.4 \times 0.4 \times 0.6 \times 0.3 = 0.0288$$ Thus, the probability of obtaining this sequence of states as a result of the actions taken is **0.0288**. Would you like further details on any specific part of the solution, or do you have any other questions? ### 5 Related Questions: 1. How would the probability change if a different sequence of actions was taken? 2. What is the significance of transition probabilities in a Markov Decision Process? 3. How can the policy be optimized based on these probabilities? 4. What role does stochasticity play in reinforcement learning environments? 5. How would the result differ if the environment were deterministic? ### Tip: When analyzing stochastic processes, it's helpful to visualize the transition probabilities as a state-action diagram to better understand the transitions.

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Math Problem Analysis

Mathematical Concepts

Markov Processes
Stochastic Processes
Probability Theory

Formulas

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Theorems

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Suitable Grade Level

Advanced Undergraduate