 Using a probability logic with linear combinations, we can abbreviate the conditional probability \(P(\phi\mid \psi)\ge q\) by \(P(\phi \wedge \psi) - qP(\psi)\ge 0\). In a modal setting, an operator \([!\psi]\) can be added to the language, such that \(M,w\models [!\psi]\phi\) if and only if \(M',w\models \phi\), where \(M'\) is the model obtained from \(M\) by revising the probabilities of each world by \(\psi\). Note that \([!\psi](P(\phi)\ge q)\) differs from \(P(\phi\mid \psi)\ge q\), in that in \([!\psi](P(\phi)\ge q)\), the interpretation of probability terms inside \(\phi\) are affected by the revision by \(\psi\), whereas in \(P(\phi\mid \psi)\ge q\), they are not, which is why \(P(\phi\mid \psi)\ge q\) nicely unfolds into another probability formula. However, \([!\psi]\phi\) does unfold too, but in more steps: 