 Replacement can be used as a kind of “Sheffer stroke” for belief revision, i.e. as an operation in terms of which the other operations can be defined. Contraction by \(p\) can be defined as \(K[p/\smtop]\) and revision by \(p\) as \(K[\smbot/p]\), where \(\smbot\) is falsum and \(\smtop\) is tautology. Provided that the unperformable suboperation of removing the tautology \(\smtop\) is treated as an empty suboperation, expansion by \(p\) can be defined as \(K[\smtop/p]\).