Final answer:
Indefeasible Title is a core concept in the registration system in law that protects the rights of bona fide purchasers who acquire property without notice of competing claims or title defects.
Step-by-step explanation:
The core of the registration system in law is the concept of Indefeasible Title. This refers to a legal principle that protects the rights of a bona fide purchaser who acquires property without notice of any competing claims or defects in the title. In simpler terms, it means that if someone buys a property in good faith and without knowledge of any conflicting interests, their ownership is protected and cannot be revoked.