Contextual pathognomony: a computationally useful extension of pathognomony

Lack of adequate focus in problem-solving is a common problem in abductive expert systems. Pathognomonic findings could theoretically provide such focus, but their rarity in most domains makes the concept computationally useless. Pople's concept of constrictor is a useful extension of the concept of pathognomony. By relaxing the focus from a disease to a class of disease, constrictors have less theoretical power than pathognomonic symptoms, but they are more ubiquitous, thus more computationally useful. Similarly, this paper introduces the concept of contextual pathognomony. Contextual pathognomony is an extension of pathognomony that takes into account the current diagnostic context. Like constrictors, contextual pathognomony is more ubiquitous, thus more computationally useful, than pathognomony. Following the description of this new concept, this paper reports and analyses an experiment showing the existence and utility of contextual pathognomony in providing focus to abductive reasoning in the domain of alloantibody identification.