 
(snd ((pair1 "hello") 42))
;=&gt; 42

(snd ((pair2 "hello") 42))
;=&gt; 42
</code></pre>
<p>The variable name <code>w</code> that was chosen is said <em>fresh</em>, and in this case the renaming is “safe”: the two-terms <code>pair1</code> and <code>pair2</code> are alpha-convertible.</p>
<p>In the practice of programming, we all now the importance of choosing good names for function parameters. This degree of freedom is thanks to alpha-conversion.</p>
<h3><a href="#beta-reduction" id="beta-reduction">