Ccalc (Causal theory calculator)
Released 2000
The Causal Calculator CCalc is a system for representing commonsense knowledge about action and change. It implements a fragment of the causal logic described in the paper "Nonmonotonic causal theories" by Enrico Giunchiglia, Joohyung Lee, Vladimir Lifschitz, Norman McCain and Hudson Turner (Artificial Intelligence, Vol. 153, 2004, pp. 49-104).