A collective right to the city A collective right to the city was seminally articulated by the French philosopher Henri Lefebvre, a right understood not simply as individual access to the goods, services, and spaces of the city but as the right to change the city in accordance with our deepest desires, to steer the very process of urbanization and the way in which the city nurtures the kinds of people we wish to become. Michael Sorkin, 20 Minutes in Manhattan The Help-Yourself City rights
The problem with trees Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as: HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS only to find a reference to another leaf: Please see HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww