 In formalizing the undercutting rebuttal, Pollock introduces a new connective, \(\otimes\), where \(p \otimes q\) means that it is not the case that \(p\) wouldn’t be true unless \(q\) were true. Pollock uses rules, rather than conditional propositions, to express the prima facie relation. If he had, instead, introduced a special connective \(\Rightarrow\), with \(p \Rightarrow q\) meaning that \(p\) would be a prima facie reason for \(q\), then undercutting defeaters could be represented by means of negating this conditional. To express the fact that \(r\) is an undercutting defeater of \(p\) as a prima facie reason for \(q\), we could state both that \((p \Rightarrow q)\) and \(\neg((p \amp r) \Rightarrow q)\).