ICS Theory Group

January 29, Winter Quarter 2010: Theory Seminar

1:00pm in 1423 Bren Hall

Retroactive Data Structures

Joe Simons, UC Irvine

Presenting a paper by Erik D. Demaine, John Iacono, Stefan Langerman

Abstract: We introduce a new data structuring paradigm in which operations can be performed on a data structure not only in the present, but also in the past. In this new paradigm, called retroactive data structures, the historical sequence of operations performed on the data structure is not fixed. The data structure allows arbitrary insertion and deletion of operations at arbitrary times, subject only to consistency requirements. We initiate the study of retroactive data structures by formally defining the model and its variants. We prove that, unlike persistence, efficient retroactivity is not always achievable. Thus, we present efficient retroactive data structures for queues, doubly ended queues, priority queues, union-find, and decomposable search structures.