Domain Driven Design, Business Domains
The interesting problems. These are the activities the company is performing differently from its competitors and from which it gains its competitive advantage.
The solved problems. These are the things all companies are doing in the same way. There is no room or need for innovation here; rather than creating in-house implementations, it’s more cost-effective to use existing solutions.
The problems with obvious solutions. These are the activities the company likely has to implement in-house, but that do not provide any competitive advantage.