The 3 knowledge areas (KA) scope, time, and cost do not have a specific project management plan, instead they are included in the project management plan.

Other KA (quality, procurement, etc.) have a specific management plan that is an input of their different processes.

Why dont' we have the project management plan as an input of most/all all processes of the KA scope, time, and cost? The project management plan should provide guidance on the management of those differnet processes, hence should be an input.

Page 82 of the PMBOK (4th edition) said that the development project management plan creates subsidiary plans that include: scope management plan (introduction to chapter 5), cost management plan (introduction to chapter 7), schedule management plan. I did not see any further references to those plans, when are they defined?