It is not hard to see that if agent \(i\) knows that \(E\) then \(i\) (robustly, strongly) believes that \(E\). However, much more can be said about the logical relationship between these different notions. (The logic of these notions has been extensively studied by Alexandru Baltag and Sonja Smets in a series of articles, see Baltag &amp; Smets 2009 in Other Internet Resources for references.)