CRDT: conflict-free replicated data type

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Tags: #crdt #distributed

CRDT. conflict-free replicated data type.md

Operations on CRDTs need to adhere to the following rules:

• Associativity (a+(b+c)=(a+b)+c), so that grouping doesn’t matter.
• Commutativity (a+b=b+a), so that order of application doesn’t matter.
• Idempotence (a+a=a), so that duplication doesn’t matter.

Data types as well as operations have to be specifically crafted to meet these rules. CRDTs have known implementations for counters, registers, sets, graphs, and others.