Hierarchy in Descriptions

Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program supported in part by the Advanced Research Projects Agency of the Department of Defense and monitored by the Office of Naval Research under Contract Number N00014-70-A-0362-0005. Vision Flashes are informal papers intended for internal use.Organization of knowledge requires the flexible use of hierarchy in descriptions. This memo attempts to catalog the issues related to recognizing and executing such descriptions, drawing examples primarily from the blocks world.MIT Artificial Intelligence Laboratory Robotics Sectio