Answers.Body: <p>I assume this is an iterative function. It means the current <span class="math-container">$V(S_t)$</span> <strong>is</strong> the sum of the previous plus some adjustment. The arrow is like an <strong>assignment</strong>.</p>
  
  <p>In code, you would do</p>
  
  <pre><code>vst = vst + alpha * (gt - vst)
  </code></pre>
  
  <p>So <code>vst</code> will be overwritten. </p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-02-16T17:44:46.053Z
Answers.LastActivityDate: 2020-02-16T20:07:49.210Z
Answers.LastEditDate: 2020-02-16T20:07:49.210Z
Answers.UserDisplayName: Dirk N
Body: <p>What is the purpose of the arrow <span class="math-container">$\leftarrow$</span> in the formula below? </p>
  
  <p><span class="math-container">$$V(S_t) \leftarrow V(S_t) + \alpha \left[ G_t - V(S_t) \right]$$</span></p>
  
  <p>I presume it's not the same as 'equals'.</p>
  
Tags: <reinforcement-learning><notation><value-functions>
Title: What is the purpose of the arrow $\leftarrow$ in this formula?
UserDisplayName: mason7663
ThreadText: # What is the purpose of the arrow $\leftarrow$ in this formula?
  
  (Asked by: username_0 on 2020-02-16)
  
  What is the purpose of the arrow $\leftarrow$ in the formula below?
  
  $$V(S\_t) \leftarrow V(S\_t) + \alpha \left[ G\_t - V(S\_t) \right]$$
  
  I presume it's not the same as 'equals'.
  
  **Tags:** reinforcement-learning, notation, value-functions
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2020-02-16. Score: 2 | Accepted answer
  
  I assume this is an iterative function. It means the current $V(S\_t)$ **is** the sum of the previous plus some adjustment. The arrow is like an **assignment**.
  
  In code, you would do
  
  ```
  vst = vst + alpha * (gt - vst)
  
  ```
  
  So `vst` will be overwritten.
  
  
  ---
  
  