4.5 Interaction of the three levels

The PTF model acts like a logical filter:

• The process defines the states.

• The technology establishes the real signal world.

• The Function connects both in the system layer.

When all three levels are correct, a complete SEQ results automatically. If a level description is missing, ambiguity arises — and that can no longer be fixed in the program.

PTF is therefore not optional, but the methodological entry point for every Selmo process.