title: how can i prove that this grammar is ambiguous?
body: <pre><code>S -&gt; bA|aB
  A -&gt; a|aS|bAA
  B -&gt; b|bS|aBB
  </code></pre>
  
  <p>Any easy method other than trying to find a string that would generate two parse trees ?</p>
  
  <p>Can someone please give me a string that can prove this.</p>