Process
This is about staring at a moving process (e.g. windmill) and trying to understand what is going on. (The most common thing people say here is monovariants or invariants, but that's only one example of a way you can understand a process.) In a lot of ways it's like the Rigid unit, except your data is way less concrete, and in some cases unobtainable, so you'll be applying the same intuition in a more hostile environment.
This unit is about analyzing processes given to you in the problem (e.g. two-player games). Unlike Rigid, the structures in this unit might be more difficult or even impossible to analyze completely, so intuition will be very important here. There will be quite some problems from well-known sources such as the ISL, USAMO, and others. Generally, this is considered to be a difficult D-level unit.
Notable problems
- USA TST 2017/4: This problem was used in the ENTRY test in OTIS.
- USA TST 2015/3: A required problem in the unit.