Relavance stores its data atomicly. Each value of each concept only stored once (unique). The associations between the concepts can be stored many times. Because there is an automated historic data collection and also because of data deduplication.
Firstname "Jan" can be associated with Lastname "Janssen" and "Klaassen".
The Firstname "Jan" is only stored once. The associations between Firstname and Lastname are stored multiple times
It saves up to 70% of storage.