title: Under what conditions does the reference count in Python increment/decrement?
body: <p>I know that in Python, garbage collection for an object is triggered when an object's <em>reference count</em> reaches 0. </p>
  
  <p><a href="https://docs.python.org/3.8/c-api/intro.html#objects-types-and-reference-counts" rel="nofollow noreferrer">https://docs.python.org/3.8/c-api/intro.html#objects-types-and-reference-counts</a></p>
  
  <p>But I'm struggling to understand what exactly are the conditions that trigger the increment/decrementing of the  reference count.</p>
  
  <p>In particular,</p>
  
  <p>(1) I know the count is incremented for each <em>reference</em> to an object... but I don't know exactly what is meant by a <em>reference</em> in the context of Python. I'm struggling to understand how references differ from, say, names or variables. What exactly is a <em>reference</em> in Python? (examples extra-appreciated)</p>
  
  <p>and</p>
  
  <p>(2) 
  What are the conditions which trigger the decrementing of the reference count?</p>