 Restall (2000) showed that \(\osim (A \wedge B) \vdash (\osim A \vee \osim B)\) corresponds to the mixed frame condition  \[ \forall x \forall y_1 \forall y_2 ((xCy_1 \amp xCy_2) \Rightarrow \exists z (y_1 \leq z \amp y_ 2 \leq z \amp xCz)).\] 