Tombstone Transformation Functions for Ensuring Consistency in Collaborative Editing Systems

Abstract

http://ieeexplore.ieee.org/In collaborative editing, consistency maintenance of the copies of shared data is a critical issue. In the last decade, Operational Transformation (OT) approach revealed as a suitable mechanism for maintaining consistency. Unfortunately, none of the published propositions relying on this approach are able to satisfy the mandatory correctness properties TP1 and TP2 defined in the Ressel's framework. This paper addresses this correctness issue by proposing a new way to model shared state by retaining tombstones when elements are removed. An instantiation of the proposed model for a linear data structure and the related transformation functions are provide

Improving Textual Merge Result

“…We adapt the Tombstone Transformation Functions (TTF) approach [25] to avoid these kind of conflicts. Before explaining our method we describe TTF algorithm.…”

An Undo Framework for P2P Collaborative Editing

“…A detailed explanation of the TTF approach and its correctness can be found in [17]. The main idea of the model is to keep deleted characters as tombstones.…”

“…Indeed, many hand-proven transformation functions were finally revealed false (all counter examples can be found in [17]). …”

Optimistic Replication and Resolution

“…TP2 is necessary if replay is in arbitrary order, e.g., in a peer-to-peer system. The vast majority of published non-serialised OT algorithms have been shown to violate TP2 [5].…”