 To model the degree of entrenchment, a relation \(\preceq\) is introduced holding between sentences of the language \(\mathbf{L}\). The notation \(\alpha \preceq \beta\) is pronounced ‘\(\alpha\) is at most as entrenched as \(\beta\).’ Gärdenfors (1988) requires that the relation satisfies the following postulates. For all \(\alpha , \beta , \gamma\) in \(\mathbf{L}\): 