For technicians and planning theorists, the problem of complexity was the crucial problem at that time: planning runs on complexity, the planning entity stands outside of what it plans and does not have the "Requisite Variety" (Ashby), i.e. the possibility to assume as many states as what it plans or as the world outside. It must reduce complexity, as the formula is then called. It must try to find elegant solutions to much more difficult problems. It must simplify. It has to engineer, abstract, form models, and then try to control systems through such models.
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LUHMANN, Niklas, 2004. Einführung in die Systemtheorie. 2. Aufl. Heidelberg: Carl-Auer-Verl. Sozialwissenschaften. ISBN 3-89670-459-1, p. 236.
reduces the Complexity of all possible Relationships to one: Containment.