% % Simplified Event Calculus (SEC) % % \fullciteA[pp. 252--253, 260]{Shanahan:1997} % % @book{Shanahan:1997, % author = "Murray Shanahan", % year = "1997", % title = "Solving the Frame Problem", % address = "Cambridge, MA", % publisher = "MIT Press", % } % % @techreport{Kowalski:1986, % author = "Robert A. Kowalski", % year = "1986", % title = "Database updates in the event calculus", % institution = "London: Imperial College of Science, Technology, and Medicine", % number = "DOC 86/12", % } % % (SEC1) holds_at(F,T2) :- timepoint(T1), timepoint(T2), fluent(F), event(E), happens(E,T1), initiates(E,F,T1), T1