The Ramifications of Sharing in Data Structures

Add to your list(s) Download to your calendar using vCal

• Jules Villard, UCL
• Friday 15 March 2013, 16:00-17:00
• UG09 Learning Centre.

If you have a question about this talk, please contact Paul Levy.

Programs manipulating mutable data structures with intrinsic sharing present a challenge for modular verification. Deep aliasing inside data structures dramatically complicates reasoning in isolation over parts of these objects because changes to one part of the structure (say, the left child of a dag node) can affect other parts (the right child or some of its descendants) that may point into it. The result is that finding intuitive and compositional proofs of correctness is usually a struggle. We propose a compositional proof system that enables local reasoning in the presence of sharing.

While the AI “frame problem” elegantly captures the reasoning required to verify programs without sharing, we contend that natural reasoning about programs with sharing instead requires an answer to a different and more challenging AI problem, the “ramification problem”: reasoning about the indirect consequences of actions. Accordingly, we present a Ramify proof rule that attacks the ramification problem head-on and show how to reason with it. Our framework is valid in any separation logic and permits sound compositional and local reasoning in the context of both specified and unspecified sharing. This talk will be illustrated by proofs of examples manipulating dags, graphs, and overlaid data structures.

This is joint work with Aquinas Hobor (National University of Singapore).

This talk is part of the Theoretical computer science seminar series.

This talk is included in these lists:

• Computer Science Departmental Series
• Computer Science Distinguished Seminars
• Theoretical computer science seminar
• UG09 Learning Centre
• computer sience

Note that ex-directory lists are not shown.