 The formula \(\forall x P(x) \vee \forall x Q(x)\) is derived at line 4 and 5 on two respective conditions: \(\{\exists x P(x) \wedge \neg \forall x P(x)\}\) and \(\{\exists x Q(x) \wedge \neg \forall x Q(x)\}\). Neither \(\exists x P(x) \wedge \neg \forall x P(x)\) nor \(\exists x Q(x) \wedge \neg \forall x Q(x)\) is derivable on the condition ∅. However, both are part of the (minimal) disjunction of abnormalities derived at line 6. According to one strategy, the minimal abnormality strategy, the premises are interpreted in such a way that as many abnormalities as possible are considered to be false, which leaves us with two interpretations: one in which \(\exists x P(x) \wedge \neg \forall x P(x)\) holds while \(\exists x Q(x) \wedge \neg \forall x Q(x)\) is false, and another one in which \(\exists x Q(x) \wedge \neg \forall x Q(x)\) holds while \(\exists x P(x) \wedge \neg \forall x P(x)\) is false. In both interpretations either the assumption of line 4 or the assumption of line 5 holds which means that in either interpretation the defeasible inference to \(\forall x P(x) \vee \forall x Q(x)\) goes through. Thus, according to the minimal abnormality strategy neither line 4 nor line 5 is marked (we omit the technical details). Another strategy, the reliability strategy, is more cautious. According to it any line that involves an abnormality in its condition that is part of a minimal disjunction of abnormalities derived on the condition ∅ is marked. This means that in our example, lines 4 and 5 are marked. 