 In plausibility semantics (briefly introduced in  Section 3.6),  an agent believes propositions that hold true in all those epistemically accessible worlds that are maximal in her plausibility order. The corresponding dynamics of deliberation does not proceed by point deletion, but by soft updates modifying the agents’ plausibility ordering. For Backward Induction, a ‘radical upgrade’ \(\Uparrow\varphi\) suffices, that moves all \(\varphi\)-worlds above all \(\neg\varphi\)-worlds states while maintaining the ordering within these two sets (Baltag &amp; Smets 2008).