An Admissibility-Based Operational Transformation Framework for Collaborative Editing Systems

Operational transformation (OT) as a consistency control method has been well accepted in group editors. With OT, the users can edit any part of a shared document at any time and local responsiveness is not sensitive to communication latencies. However, established theoretical frameworks for developing OT algorithms either require transformation functions to work in all possible cases, which complicates the design of transformation functions, or include an under-formalized condition of intention preservation, which results in algorithms that cannot be formally proved and must be fixed over time to address newly discovered counterexamples. To address those limitations, this paper proposes an alternative framework, called admissibility-based transformation (ABT), that is theoretically based on formalized, provable correctness criteria and practically no longer requires transformation functions to work under all conditions. Compared to previous approaches, ABT simplifies the design and proofs of OT algorithms.