Department of Computer Science
Yale University
Alan J. Perlis Lecture Series

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May 3, 2005
10:30 a.m., AKW 200

SPEAKER: John Reynolds, Carnegie Mellon University
TITLE: An Introduction to Separation Logic

ABSTRACT: In joint work with Peter O'Hearn and others, based on early ideas of Burstall, we have developed an extension of Hoare logic that permits reasoning about low-level imperative programs that use shared mutable data structure.

The simple imperative programming language is extended with commands (not expressions) for accessing and modifying shared structures, and for explicit allocation and deallocation of storage. Assertions are extended by introducing a ``separating conjunction'' that asserts that its subformulas hold for disjoint parts of the heap, and a closely related ``separating implication''. Coupled with the inductive definition of predicates on abstract data structures, this extension permits the concise and flexible description of structures with controlled sharing.

We will survey the current development of this logic, including extensions that permit unrestricted address arithmetic, dynamically allocated arrays, recursive procedures, and shared variable concurrency. We will also discuss promising future directions.