Rule Markup language

Though my colleague Harold Boley works on it, I did not understand the important of this topic until I read the paper by Jae Kyu Lee and Mye M. Sohn “the extensiable rule markup language” in CACM May 2003. Rule markup wants to markup a normal HTML into rules and then the rules can be stored in a rule base and processed by inference engine. It is a method of managing the knowledge. Well, it is hard to markup, because of the language ambiguity.