title: [Homework Question][Finished] about Conjunctive normal form(CNF)
body: <p>It's a homework question. Can we consider the following as a CNF?</p>
  
  <pre><code>(¬x ∧ y) ∧ (x ∨ z)
  </code></pre>
  
  <p>I thinks it's a CNF just like <code>A ∧ B</code>, but my friend doesn't agree with me.</p>