cumulative causation? core? periphery?

I was going through some development stuff with my kids today and found out that there are some common misconceptions to these 3 terms. Here's to clear it up:

1) Core-periphery is to DESCRIBE the relationship between two countries / places, not to explain why there is uneven development
Eg: I'm a teacher, you're a student. Teacher-student will be the terms used to DESCRIBE our relationship, but it doesn't explain why I have more authority over you.

2) Cumulative causation is the PROCESS that leads to the uneven development between core-periphery

In summary, cumulative causation is the process in which the core becomes more developed than the periphery, by draining resources and labour from the periphery. Hence, the process explains why core and periphery, starts from being equally developed, to the core becoming more developed than the periphery.

THEREFORE
It will be inaccurate to say, one place BECAME more developed than the other because of core-periphery relationship.

Rather, it will be more accurate to say that one place BECAME more developed than another due to cumulative causation.

However, you can use core-periphery relationship to explain why the periphery is KEPT less developed than the core. To explain HOW it becomes less developed than the core, it will be more accurate to say that it is because of the PROCESS of cumulative causation.