The interpretation is that the decision made at the first node (\(d_0\)) is forgotten, and so the decision maker is uncertain about whether she is at node \(d_1\) or \(d_2\). See Osborne (2003: ch. 9 &amp; 10) for the general theory of games with imperfect information. In this section, we briefly discuss a foundational issue that arises in games with imperfect information.